31,641 results on '"Bharadwaj AS"'
Search Results
2. Visualization of atomistic optical waves in crystals
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Mun, Jungho, Bharadwaj, Sathwik, and Jacob, Zubin
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Physics - Optics ,Condensed Matter - Other Condensed Matter - Abstract
The refractive index of a matter is foundational to quantify the light-matter interaction of the medium. However, the classical description of refractive index is based on macroscopic homogenization and is limited to describing the local optical response of materials. A complete quantum description of light-matter interaction should consider nonlocality and multiple-scattering of optical responses at the atomistic lattice level. Recently, the deep microscopic optical band structure was introduced as a quantum generalization of refractive index of a medium. This quantum description unveils multiple optical eigenmodes in crystalline solids and hidden microscopic optical waves at the lattice level. In this work, we unravel the microscopic optical waves in silicon carbide. We predict and visualize hidden microscopic optical eigenwaves, which can be nonplanar and inhomogeneous even near the optical limit. Also, the nonlocal macroscopic dielectric constant of the crystal is analyzed using the microscopic optical waves as the basis. Our work establishes a general framework for picoscale electrodynamics applicable to other materials including two-dimensional materials., Comment: 6 pages, 4 figures
- Published
- 2024
3. Randomized Black-Box PIT for Small Depth +-Regular Non-commutative Circuits
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Bharadwaj, G V Sumukha and Raja, S
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Computer Science - Computational Complexity - Abstract
In this paper, we address the black-box polynomial identity testing (PIT) problem for non-commutative polynomials computed by $+$-regular circuits, a class of homogeneous circuits introduced by Arvind, Joglekar, Mukhopadhyay, and Raja (STOC 2017, Theory of Computing 2019). These circuits can compute polynomials with a number of monomials that are doubly exponential in the circuit size. They gave an efficient randomized PIT algorithm for +-regular circuits of depth 3 and posed the problem of developing an efficient black-box PIT for higher depths as an open problem. We present a randomized black-box polynomial-time algorithm for +-regular circuits of any constant depth. Specifically, our algorithm runs in $s^{O(d^2)}$ time, where $s$ and $d$ represent the size and the depth of the $+$-regular circuit, respectively. Our approach combines several key techniques in a novel way. We employ a nondeterministic substitution automaton that transforms the polynomial into a structured form and utilizes polynomial sparsification along with commutative transformations to maintain non-zeroness. Additionally, we introduce matrix composition, coefficient modification via the automaton, and multi-entry outputs--methods that have not previously been applied in the context of black-box PIT. Together, these techniques enable us to effectively handle exponential degrees and doubly exponential sparsity in non-commutative settings, enabling polynomial identity testing for higher-depth circuits. Our work resolves an open problem from \cite{AJMR19}. In particular, we show that if $f$ is a non-zero non-commutative polynomial in $n$ variables over the field $F$, computed by a depth-$d$ $+$-regular circuit of size $s$, then $f$ cannot be a polynomial identity for the matrix algebra $\mathbb{M}_{N}(F)$, where $N= s^{O(d^2)}$ and the size of the field $F$ depending on the degree of $f$., Comment: 49 pages, 6 figures
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- 2024
4. OpenFLAME: Building a large scale federated localization and mapping service
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Bharadwaj, Sagar, Wang, Luke, Liang, Michael, Williams, Harrison, Liang, Ivan, Seshan, Srinivasan, and Rowe, Anthony
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Computer Science - Distributed, Parallel, and Cluster Computing - Abstract
The widespread availability of maps has enabled the development of numerous location-based applications, including navigation, ride-sharing, fitness tracking, gaming, robotics, and augmented reality. Today, the maps that power these services are predominantly controlled by a few large corporations and mostly cover outdoor spaces. As the use of these applications expands and indoor localization technologies advance, we are seeing the need for a scalable, federated location management system that can extend into private spaces. We introduce OpenFLAME (Open Federated Localization and Mapping Engine), the first federated and decentralized localization service. OpenFLAME links servers that handle localization for specific regions, providing applications with a seamless global view. Creating a federated localization system poses challenges, such as discovering the appropriate servers for a region and integrating services managed by independent providers. To address these issues and ensure scalability, we leverage Domain Name System (DNS) for service discovery and implement map abstractions to retrieve and merge locations across different maps. Our trace-driven study demonstrates that federated localization across remote servers is feasible with acceptable query latencies. To highlight the potential of the system, we developed an augmented reality navigation application for a large indoor space, showing that OpenFLAME can successfully power location-based applications.
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- 2024
5. Exploring vector dark matter via effective interactions
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Bharadwaj, Hrishabh
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High Energy Physics - Phenomenology - Abstract
We explore the properties of self-conjugate dark matter (DM) particles that predominantly interact with Standard Model electroweak gauge bosons, using an effective field theory approach. The study emphasizes effective contact interactions, invariant under the Standard Model gauge group, between vector DM and SM-neutral electroweak gauge bosons. Focusing on interaction terms up to dimension-8, we establish constraints on the model parameters based on the observed DM relic density and indirect detection signals. We also examine the prospects for dark matter-nucleon scattering in direct detection experiments. In addition, we analyze the sensitivity of low-energy LEP data to the pair production of light DM particles (with masses up to 80 GeV). Finally, we assess the potential of the proposed International Linear Collider (ILC) to probe these effective operators through the detection of DM particles produced in association with mono-photons., Comment: 13 pages, 7 figures
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- 2024
6. Quantum Carleman linearisation efficiency in nonlinear fluid dynamics
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Gonzalez-Conde, Javier, Lewis, Dylan, Bharadwaj, Sachin S., and Sanz, Mikel
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Quantum Physics ,Physics - Fluid Dynamics - Abstract
Computational fluid dynamics (CFD) is a specialised branch of fluid mechanics that utilises numerical methods and algorithms to solve and analyze fluid-flow problems. One promising avenue to enhance CFD is the use of quantum computing, which has the potential to resolve nonlinear differential equations more efficiently than classical computers. Here, we try to answer the question of which regimes of nonlinear partial differential equations (PDEs) for fluid dynamics can have an efficient quantum algorithm. We propose a connection between the numerical parameter, $R$, that guarantees efficiency in the truncation of the Carleman linearisation, and the physical parameters that describe the fluid flow. This link can be made thanks to the Kolmogorov scale, which determines the minimum size of the grid needed to properly resolve the energy cascade induced by the nonlinear term. Additionally, we introduce the formalism for vector field simulation in different spatial dimensions, providing the discretisation of the operators and the boundary conditions.
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- 2024
7. Adaptive Multi Scale Document Binarisation Using Vision Mamba
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Azfar, Mohd., Bharadwaj, Siddhant, and Sasikumar, Ashwin
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Computer Science - Computer Vision and Pattern Recognition - Abstract
Enhancing and preserving the readability of document images, particularly historical ones, is crucial for effective document image analysis. Numerous models have been proposed for this task, including convolutional-based, transformer-based, and hybrid convolutional-transformer architectures. While hybrid models address the limitations of purely convolutional or transformer-based methods, they often suffer from issues like quadratic time complexity. In this work, we propose a Mamba-based architecture for document binarisation, which efficiently handles long sequences by scaling linearly and optimizing memory usage. Additionally, we introduce novel modifications to the skip connections by incorporating Difference of Gaussians (DoG) features, inspired by conventional signal processing techniques. These multiscale high-frequency features enable the model to produce high-quality, detailed outputs.
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- 2024
8. Image Generation from Image Captioning -- Invertible Approach
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Menon, Nandakishore S, Kamanchi, Chandramouli, and Diddigi, Raghuram Bharadwaj
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Computer Science - Computer Vision and Pattern Recognition - Abstract
Our work aims to build a model that performs dual tasks of image captioning and image generation while being trained on only one task. The central idea is to train an invertible model that learns a one-to-one mapping between the image and text embeddings. Once the invertible model is efficiently trained on one task, the image captioning, the same model can generate new images for a given text through the inversion process, with no additional training. This paper proposes a simple invertible neural network architecture for this problem and presents our current findings., Comment: Accepted as Tiny Paper at ICVGIP 2024 conference
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- 2024
9. Nature of spin glass order in physical dimensions
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Vedula, Bharadwaj, Moore, M. A., and Sharma, Auditya
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Condensed Matter - Disordered Systems and Neural Networks - Abstract
We have studied the diluted Heisenberg spin glass model in a 3-component random field for the commonly-used one-dimensional long-range model where the probability that two spins separated by a distance $r$ interact with one another falls as $1/r^{2 \sigma}$, for two values of $\sigma$, $0.75$ and $0.85$. No de Almeida-Thouless line is expected at these $\sigma$ values. The spin glass correlation length $\xi_{\text{SG}}$ varies with the random field as expected from the Imry-Ma argument and the droplet scaling picture of spin glasses. However, when $\xi_{\text{SG}}$ becomes comparable to the system size $L$, there are departures which we attribute to the features deriving from the TNT picture of spin glasses. For the case $\sigma =0.85$ these features go away for system sizes with $L >L^*$, where $L^*$ is large ($\approx 4000-8000$ lattice spacings). In the case of $\sigma = 0.75$ we have been unable to study large enough systems to determine its value of $L^*$. We sketch a renormalization group scenario to explain how these features could arise. On this scenario finite size effects on the droplet scaling picture in low-dimensional spin glasses produce TNT features and some aspects of Parisi's replica symmetry breaking theory of the Sherrington-Kirkpatrick model., Comment: 11 pages, 3 + 3 figures, 2 tables
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- 2024
10. UVCANDELS: Catalogs of photometric redshifts and galaxy physical properties
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Mehta, Vihang, Rafelski, Marc, Sunnquist, Ben, Teplitz, Harry I., Scarlata, Claudia, Wang, Xin, Fontana, Adriano, Hathi, Nimish P., Iyer, Kartheik G., Alavi, Anahita, Colbert, James, Grogin, Norman, Koekemoer, Anton, Nedkova, Kalina V., Hayes, Matthew, Prichard, Laura, Siana, Brian, Smith, Brent M., Windhorst, Rogier, Ashcraft, Teresa, Bagley, Micaela, Baronchelli, Ivano, Barro, Guillermo, Blanche, Alex, Broussard, Adam, Carleton, Timothy, Chartab, Nima, Codoreanu, Alex, Cohen, Seth, Conselice, Christopher, Dai, Y. Sophia, Darvish, Behnam, Dave, Romeel, DeGroot, Laura, De Mello, Duilia, Dickinson, Mark, Emami, Najmeh, Ferguson, Henry, Ferreira, Leonardo, Finkelstein, Keely, Finkelstein, Steven, Gardner, Jonathan P., Gawiser, Eric, Gburek, Timothy, Giavalisco, Mauro, Grazian, Andrea, Gronwall, Caryl, Guo, Yicheng, Haro, Pablo Arrabal, Hemmati, Shoubaneh, Howell, Justin, Jansen, Rolf A., Ji, Zhiyuan, Kaviraj, Sugata, Kim, Keunho J., Kurczynski, Peter, Lazar, Ilin, Lucas, Ray A., MacKenty, John, Mantha, Kameswara Bharadwaj, Martin, Alec, Martin, Garreth, McCabe, Tyler, Mobasher, Bahram, Morales, Alexa M., O'Connell, Robert, Olsen, Charlotte, Otteson, Lillian, Ravindranath, Swara, Redshaw, Caleb, Rutkowski, Michael, Robertson, Brant, Sattari, Zahra, Soto, Emmaris, Sun, Lei, Taamoli, Sina, Vanzella, Eros, Yung, L. Y. Aaron, and Zabelle, Bonnabelle
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Astrophysics - Astrophysics of Galaxies - Abstract
The UltraViolet imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey Fields (UVCANDELS) program provides deep HST F275W and F435W imaging over four CANDELS fields (GOODS-N, GOODS-S, COSMOS, and EGS). We combine this newly acquired UV imaging with existing HST imaging from CANDELS as well as existing ancillary data to obtain robust photometric redshifts and reliable estimates for galaxy physical properties for over 150,000 galaxies in the $\sim$430 arcmin$^2$ UVCANDELS area. Here, we leverage the power of the new UV photometry to not only improve the photometric redshift measurements in these fields, but also constrain the full redshift probability distribution combining multiple redshift fitting tools. Furthermore, using the full UV-to-IR photometric dataset, we measure the galaxy physical properties by fitting templates from population synthesis models with two different parameterizations (flexible and fixed-form) of the star-formation histories (SFHs). Compared to the flexible SFH parametrization, we find that the fixed-form SFHs systematically underestimate the galaxy stellar masses, both at the low- ($\lesssim10^9 M_\odot$) and high- ($\gtrsim10^{10} M_\odot$) mass end, by as much as $\sim0.5$ dex. This underestimation is primarily due the limited ability of fixed-form SFH parameterization to simultaneously capture the chaotic nature of star-formation in these galaxies., Comment: 22 pages, 6 figures; accepted to ApJS; catalogs available via MAST
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- 2024
11. The Tracking Tapered Gridded Estimator for the 21-cm power spectrum from MWA drift scan observations II: The Missing Frequency Channels
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Elahi, Khandakar Md Asif, Bharadwaj, Somnath, Chatterjee, Suman, Sarkar, Shouvik, Choudhuri, Samir, Sethi, Shiv, and Patwa, Akash Kumar
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Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Missing frequency channels pose a problem for estimating $P(k_\perp,k_\parallel)$ the redshifted 21-cm power spectrum (PS) from radio-interferometric visibility data. This is particularly severe for the Murchison Widefield Array (MWA), which has a periodic pattern of missing channels that introduce spikes along $k_\parallel$. The Tracking Tapered Gridded Estimator (TTGE) overcomes this by first correlating the visibilities in the frequency domain to estimate the multi-frequency angular power spectrum (MAPS) $C_\ell(\Delta\nu)$ that has no missing frequency separation $\Delta\nu$. We perform a Fourier transform along $\Delta\nu$ to estimate $P(k_\perp,k_\parallel)$. Considering our earlier work, simulations demonstrate that the TTGE can estimate $P(k_\perp,k_\parallel)$ without any artifacts due to the missing channels. However, the spikes were still found to persist for the actual data, which is foreground-dominated. The current work presents a detailed investigation considering both simulations and actual data. We find that the spikes arise due to a combination of the missing channels and the strong spectral dependence of the foregrounds. Based on this, we propose and demonstrate a technique to mitigate the spikes. Applying this, we find the values of $P(k_\perp,k_\parallel)$ in the region $0.004 \leq k_\perp \leq 0.048\,{\rm Mpc^{-1}}$ and $k_\parallel > 0.35 \,{\rm Mpc^{-1}}$ to be consistent with zero within the expected statistical fluctuations. We obtain the $2\sigma$ upper limit of $\Delta_{\rm UL}^2(k)=(918.17)^2\,{\rm mK^2}$ at $k=0.404\,{\rm Mpc^{-1}}$ for the mean squared brightness temperature fluctuations of the $z=8.2$ epoch of reionization (EoR) 21-cm signal. This upper limit is from just $\sim 17$ minutes of observation for a single pointing direction. We expect tighter constraints when we combine all $162$ different pointing directions of the drift scan observation., Comment: 11 pages, 16 figures, comments are welcome
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- 2024
12. Harnessing Wavelet Transformations for Generalizable Deepfake Forgery Detection
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Baru, Lalith Bharadwaj, Patel, Shilhora Akshay, and Boddeda, Rohit
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Artificial Intelligence ,Computer Science - Machine Learning - Abstract
The evolution of digital image manipulation, particularly with the advancement of deep generative models, significantly challenges existing deepfake detection methods, especially when the origin of the deepfake is obscure. To tackle the increasing complexity of these forgeries, we propose \textbf{Wavelet-CLIP}, a deepfake detection framework that integrates wavelet transforms with features derived from the ViT-L/14 architecture, pre-trained in the CLIP fashion. Wavelet-CLIP utilizes Wavelet Transforms to deeply analyze both spatial and frequency features from images, thus enhancing the model's capability to detect sophisticated deepfakes. To verify the effectiveness of our approach, we conducted extensive evaluations against existing state-of-the-art methods for cross-dataset generalization and detection of unseen images generated by standard diffusion models. Our method showcases outstanding performance, achieving an average AUC of 0.749 for cross-data generalization and 0.893 for robustness against unseen deepfakes, outperforming all compared methods. The code can be reproduced from the repo: \url{https://github.com/lalithbharadwajbaru/Wavelet-CLIP}
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- 2024
13. Gradient-Driven 3D Segmentation and Affordance Transfer in Gaussian Splatting Using 2D Masks
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Joseph, Joji, Amrutur, Bharadwaj, and Bhatnagar, Shalabh
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Robotics - Abstract
3D Gaussian Splatting has emerged as a powerful 3D scene representation technique, capturing fine details with high efficiency. In this paper, we introduce a novel voting-based method that extends 2D segmentation models to 3D Gaussian splats. Our approach leverages masked gradients, where gradients are filtered by input 2D masks, and these gradients are used as votes to achieve accurate segmentation. As a byproduct, we discovered that inference-time gradients can also be used to prune Gaussians, resulting in up to 21% compression. Additionally, we explore few-shot affordance transfer, allowing annotations from 2D images to be effectively transferred onto 3D Gaussian splats. The robust yet straightforward mathematical formulation underlying this approach makes it a highly effective tool for numerous downstream applications, such as augmented reality (AR), object editing, and robotics. The project code and additional resources are available at https://jojijoseph.github.io/3dgs-segmentation., Comment: Preprint, Under review for ICRA 2025
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- 2024
14. UniLCD: Unified Local-Cloud Decision-Making via Reinforcement Learning
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Sengupta, Kathakoli, Shagguan, Zhongkai, Bharadwaj, Sandesh, Arora, Sanjay, Ohn-Bar, Eshed, and Mancuso, Renato
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Computer Science - Robotics - Abstract
Embodied vision-based real-world systems, such as mobile robots, require a careful balance between energy consumption, compute latency, and safety constraints to optimize operation across dynamic tasks and contexts. As local computation tends to be restricted, offloading the computation, ie, to a remote server, can save local resources while providing access to high-quality predictions from powerful and large models. However, the resulting communication and latency overhead has led to limited usability of cloud models in dynamic, safety-critical, real-time settings. To effectively address this trade-off, we introduce UniLCD, a novel hybrid inference framework for enabling flexible local-cloud collaboration. By efficiently optimizing a flexible routing module via reinforcement learning and a suitable multi-task objective, UniLCD is specifically designed to support the multiple constraints of safety-critical end-to-end mobile systems. We validate the proposed approach using a challenging, crowded navigation task requiring frequent and timely switching between local and cloud operations. UniLCD demonstrates improved overall performance and efficiency, by over 35% compared to state-of-the-art baselines based on various split computing and early exit strategies., Comment: ECCV 24
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- 2024
15. A logical alarm for misaligned binary classifiers
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Corrada-Emmanuel, Andrés, Parker, Ilya, and Bharadwaj, Ramesh
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Computer Science - Machine Learning ,Computer Science - Artificial Intelligence ,62G99 (Primary), 14Q99 (Secondary) ,I.2.3 - Abstract
If two agents disagree in their decisions, we may suspect they are not both correct. This intuition is formalized for evaluating agents that have carried out a binary classification task. Their agreements and disagreements on a joint test allow us to establish the only group evaluations logically consistent with their responses. This is done by establishing a set of axioms (algebraic relations) that must be universally obeyed by all evaluations of binary responders. A complete set of such axioms are possible for each ensemble of size N. The axioms for $N = 1, 2$ are used to construct a fully logical alarm - one that can prove that at least one ensemble member is malfunctioning using only unlabeled data. The similarities of this approach to formal software verification and its utility for recent agendas of safe guaranteed AI are discussed., Comment: 17 pages, 7 figures, under review
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- 2024
16. Simulating fluid flows with quantum computing
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Bharadwaj, Sachin S. and Sreenivasan, Katepalli R.
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Quantum Physics ,Physics - Applied Physics ,Physics - Computational Physics ,Physics - Fluid Dynamics - Abstract
The applications and impact of high fidelity simulation of fluid flows are far-reaching. They include settling some long-standing and fundamental questions in turbulence. However, the computational resources required for such efforts are extensive. Here, we explore the possibility of employing the recent computing paradigm of quantum computing to simulate fluid flows. The lure of this new paradigm is the potentially exponential advantage in memory and speed, in comparison with classical computing. This field has recently witnessed a considerable uptick in excitement and contributions. In this work, we give a succinct discussion of the progress made so far, with focus on fluid flows, accompanied by an enumeration of challenges that require sustained efforts for progress. Quantum computing of fluid flows has a promising future, but the inherently nonlinear nature of flows requires serious efforts on resolving various bottlenecks, and on synthesising progress on theoretical, numerical and experimental fronts. We present certain critical details that have not yet attracted adequate attention., Comment: 17 pages, 12 figures
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- 2024
17. Neutrino flux sensitivity to the next galactic core-collapse supernova in COSINUS
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Angloher, G., Bharadwaj, M. R., Cababie, M., Colantoni, I., Dafinei, I., De Santis, A. L., Di Marco, N., Einfalt, L., Ferella, F., Ferroni, F., Fichtinger, S., Filipponi, A., Frank, T., Friedl, M., Ge, Z., Heikinheimo, M., Hughes, M. N., Huitu, K., Kellermann, M., Maji, R., Mancuso, M., Pagnanini, L., Petricca, F., Pirro, S., Pröbst, F., Profeta, G., Puiu, A., Reindl, F., Schaeffner, K., Schieck, J., Schreiner, P., Schwertner, C., Shera, K., Stahlberg, M., Stendhal, A., Stukel, M., Tresca, C., Wagner, F., Yue, S., Zema, V., Zhu, Y., and Pagliaroli, G.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
While neutrinos are often treated as a background for many dark matter experiments, these particles offer a new avenue for physics: the detection of core-collapse supernovae. Supernovae are extremely energetic, violent and complex events that mark the death of massive stars. During their collapse stars emit a large number of neutrinos in a short burst. These neutrinos carry 99\% of the emitted energy which makes their detection fundamental in understanding supernovae. This paper illustrates how COSINUS (Cryogenic Observatory for SIgnatures seen in Next-generation Underground Searches), a sodium iodide (NaI) based dark matter search, will be sensitive to the next galactic core-collapse supernova. The experiment is composed of two separate detectors which will be sensitive to far and nearby supernovae. The inner core of the experiment will consist of NaI crystals operating as scintillating calorimeters, mainly sensitive to the Coherent Elastic Scattering of Neutrinos (CE$\nu$NS) against the Na and I nuclei. The low mass of the cryogenic detectors gives the experiment a sensitivity to close supernovae below 1kpc without pileup. They will see up to hundreds of CE$\nu$NS events from a supernova happening at 200pc. The crystals reside at the center of a cylindrical 230T water tank, instrumented with 30 photomultipliers. This tank acts as a passive and active shield able to detect the Cherenkov radiation induced by impinging charged particles from ambient and cosmogenic radioactivity. A supernova near the Milky Way Center (10kpc) will be easily detected inducing $\sim$60 measurable events, and the water tank will have a 3$\sigma$ sensitivity to supernovae up to 22kpc, seeing $\sim$10 events. This paper shows how, even without dedicated optimization, modern dark matter experiments will also play their part in the multi-messenger effort to detect the next galactic core-collapse supernova.
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- 2024
18. SPARK: Self-supervised Personalized Real-time Monocular Face Capture
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Baert, Kelian, Bharadwaj, Shrisha, Castan, Fabien, Maujean, Benoit, Christie, Marc, Abrevaya, Victoria, and Boukhayma, Adnane
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Machine Learning - Abstract
Feedforward monocular face capture methods seek to reconstruct posed faces from a single image of a person. Current state of the art approaches have the ability to regress parametric 3D face models in real-time across a wide range of identities, lighting conditions and poses by leveraging large image datasets of human faces. These methods however suffer from clear limitations in that the underlying parametric face model only provides a coarse estimation of the face shape, thereby limiting their practical applicability in tasks that require precise 3D reconstruction (aging, face swapping, digital make-up, ...). In this paper, we propose a method for high-precision 3D face capture taking advantage of a collection of unconstrained videos of a subject as prior information. Our proposal builds on a two stage approach. We start with the reconstruction of a detailed 3D face avatar of the person, capturing both precise geometry and appearance from a collection of videos. We then use the encoder from a pre-trained monocular face reconstruction method, substituting its decoder with our personalized model, and proceed with transfer learning on the video collection. Using our pre-estimated image formation model, we obtain a more precise self-supervision objective, enabling improved expression and pose alignment. This results in a trained encoder capable of efficiently regressing pose and expression parameters in real-time from previously unseen images, which combined with our personalized geometry model yields more accurate and high fidelity mesh inference. Through extensive qualitative and quantitative evaluation, we showcase the superiority of our final model as compared to state-of-the-art baselines, and demonstrate its generalization ability to unseen pose, expression and lighting., Comment: SIGGRAPH Asia 2024 Conference Paper. Project page: https://kelianb.github.io/SPARK/
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- 2024
- Full Text
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19. STAB: Speech Tokenizer Assessment Benchmark
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Vashishth, Shikhar, Singh, Harman, Bharadwaj, Shikhar, Ganapathy, Sriram, Asawaroengchai, Chulayuth, Audhkhasi, Kartik, Rosenberg, Andrew, Bapna, Ankur, and Ramabhadran, Bhuvana
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Computer Science - Computation and Language ,Computer Science - Sound ,Electrical Engineering and Systems Science - Audio and Speech Processing - Abstract
Representing speech as discrete tokens provides a framework for transforming speech into a format that closely resembles text, thus enabling the use of speech as an input to the widely successful large language models (LLMs). Currently, while several speech tokenizers have been proposed, there is ambiguity regarding the properties that are desired from a tokenizer for specific downstream tasks and its overall generalizability. Evaluating the performance of tokenizers across different downstream tasks is a computationally intensive effort that poses challenges for scalability. To circumvent this requirement, we present STAB (Speech Tokenizer Assessment Benchmark), a systematic evaluation framework designed to assess speech tokenizers comprehensively and shed light on their inherent characteristics. This framework provides a deeper understanding of the underlying mechanisms of speech tokenization, thereby offering a valuable resource for expediting the advancement of future tokenizer models and enabling comparative analysis using a standardized benchmark. We evaluate the STAB metrics and correlate this with downstream task performance across a range of speech tasks and tokenizer choices., Comment: 5 pages
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- 2024
20. Discovery and characterization of a dense sub-Saturn TOI-6651b
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Baliwal, Sanjay, Sharma, Rishikesh, Chakraborty, Abhijit, Khandelwal, Akanksha, Nikitha, K. J., Safonov, Boris S., Strakhov, Ivan A., Montalto, Marco, Eastman, Jason D., Latham, David W., Bieryla, Allyson, Prasad, Neelam J. S. S. V., Bharadwaj, Kapil K., Lad, Kevikumar A., Das, Shubhendra N., and Nayak, Ashirbad
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Astrophysics - Earth and Planetary Astrophysics - Abstract
We report the discovery and characterization of a transiting sub-Saturn exoplanet TOI-6651b using PARAS-2 spectroscopic observations. The host, TOI-6651 ($m_{V}\approx 10.2$), is a sub-giant, metal-rich G-type star with $[{\rm Fe/H}] = 0.225^{+0.044}_{-0.045}$, $T_{\rm eff} = 5940\pm110\ \mathrm{K}$, and $\log{g} = 4.087^{+0.035}_{-0.032}$. Joint fitting of the radial velocities from PARAS-2 spectrograph and transit photometric data from Transiting Exoplanet Survey Satellite (TESS) reveals a planetary mass of $61.0^{+7.6}_{-7.9}\ M_\oplus$ and radius of $5.09^{+0.27}_{-0.26}\ R_\oplus$, in a $5.056973^{+0.000016}_{-0.000018}$ day orbit with an eccentricity of $0.091^{+0.096}_{-0.062}$. TOI-6651b has a bulk density of $2.52^{+0.52}_{-0.44}\ \mathrm{g\ cm^{-3}}$, positioning it among the select few known dense sub-Saturns and making it notably the densest detected with TESS. TOI-6651b is consistent with the positive correlation between planet mass and the host star's metallicity. We find that a considerable portion $\approx$ 87% of the planet's mass consists of dense materials such as rock and iron in the core, while the remaining mass comprises a low-density envelope of H/He. TOI-6651b lies at the edge of the Neptunian desert, which will be crucial for understanding the factors shaping the desert boundaries. The existence of TOI-6651b challenges conventional planet formation theories and could be a result of merging events or significant atmospheric mass loss through tidal heating, highlighting the complex interplay of dynamical processes and atmospheric evolution in the formation of massive dense sub-Saturns., Comment: 15 pages, 12 figures
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- 2024
- Full Text
- View/download PDF
21. Wireless Integrated Authenticated Communication System (WIA-Comm)
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Bharadwaj, Amith N, Adarsh, G, N, Gurusatwik Bhatta, K, Karan, and T, Vijay B
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Computer Science - Cryptography and Security ,Electrical Engineering and Systems Science - Systems and Control - Abstract
The exponential increase in the number of devices connected to the internet globally has led to the requirement for the introduction of better and improved security measures for maintaining data integrity. The development of a wireless and authenticated communication system is required to overcome the safety threats and illegal access to the application system/data. The WIA-Comm System is the one that provides a bridge to control the devices at the application side. It has been designed to provide security by giving control rights only to the device whose MAC (physical) address has already been registered, so only authorized users can control the system. LoRa WAN technology has been used for wireless communication and Arduino IDE to develop the code for the required functionality., Comment: 6 pages, 10 figures, 3 tables
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- 2024
22. Non-invertible defects on the worldsheet
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Bharadwaj, Sriram, Niro, Pierluigi, and Roumpedakis, Konstantinos
- Subjects
High Energy Physics - Theory - Abstract
We consider codimension-one defects in the theory of $d$ compact scalars on a two-dimensional worldsheet, acting linearly by mixing the scalars and their duals. By requiring that the defects are topological, we find that they correspond to a non-Abelian zero-form symmetry acting on the fields as elements of $\text{O}(d;\mathbb{R}) \times \text{O}(d;\mathbb{R})$, and on momentum and winding charges as elements of $\text{O}(d,d;\mathbb{R})$. When the latter action is rational, we prove that it can be realized by combining gauging of non-anomalous discrete subgroups of the momentum and winding $\text{U}(1)$ symmetries, and elements of the $\text{O}(d,d;\mathbb{Z})$ duality group, such that the couplings of the theory are left invariant. Generically, these defects map local operators into non-genuine operators attached to lines, thus corresponding to a non-invertible symmetry. We confirm our results within a Lagrangian description of the non-invertible topological defects associated to the $\text{O}(d,d;\mathbb{Q})$ action on charges, giving a natural explanation of the rationality conditions. Finally, we apply our findings to toroidal compactifications of bosonic string theory. In the simplest non-trivial case, we discuss the selection rules of these non-invertible symmetries, verifying explicitly that they are satisfied on a worldsheet of higher genus., Comment: 38 pages, 5 figures
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- 2024
23. Optical and microstructural studies of femtosecond laser treated amorphous germanium thin coatings
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Kotsedi, L., Abdelmalek, A., Bharadwaj, V., Mtshali, C. B., Nuru, Z. Y., Sotillo, B., Coccia, G., Eaton, S. M., Ramponi, R., Amara, El-H., and Maaza, M.
- Subjects
Physics - Optics ,Condensed Matter - Materials Science - Abstract
The study of the relaxation mechanism of amorphous germanium after femtosecond laser irradiation is presented in this work. In particular, a thin germanium coating was deposited onto a glass substrate through the electron beam vacuum coating method. The substrate was kept at room temperature during the coating process, which resulted in a deposited layer characterized by an amorphous microstructure, as observed from the X-ray diffraction. The germanium layer was then irradiated with a femtosecond laser at 1030 nm wavelength, while varying the net fluence from 15 J cm-2 to 90 J cm-2. Moreover, an extended two temperature model was used to extract the electronic and lattice temperature of the laser heated germanium coating, showing a 32% contribution from heating due to the thermal accumulation effect. The microstructural and morphological studies of the irradiated samples were carried out using X-ray diffraction and high-resolution scanning electron microscopy. From the X-ray diffraction results, it was observed that at higher laser fluence there is an emergence of crystallinity on the germanium layer, with no evidence of oxidation. On the surface, the morphology was observed to evolve to granular sphere, attributed to melting of the material. Finally, an increase in absorbance with laser fluence was observed and the optical band gap of the coating was calculated., Comment: 21 pages, 9 figures
- Published
- 2024
24. Security Risks Due to Data Persistence in Cloud FPGA Platforms
- Author
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Zhang, Zhehang, Madabhushi, Bharadwaj, Kundu, Sandip, and Tessier, Russell
- Subjects
Computer Science - Cryptography and Security ,Computer Science - Hardware Architecture ,Computer Science - Distributed, Parallel, and Cluster Computing - Abstract
The integration of Field Programmable Gate Arrays (FPGAs) into cloud computing systems has become commonplace. As the operating systems used to manage these systems evolve, special consideration must be given to DRAM devices accessible by FPGAs. These devices may hold sensitive data that can become inadvertently exposed to adversaries following user logout. Although addressed in some cloud FPGA environments, automatic DRAM clearing after process termination is not automatically included in popular FPGA runtime environments nor in most proposed cloud FPGA hypervisors. In this paper, we examine DRAM data persistence in AMD/Xilinx Alveo U280 nodes that are part of the Open Cloud Testbed (OCT). Our results indicate that DDR4 DRAM is not automatically cleared following user logout from an allocated node and subsequent node users can easily obtain recognizable data from the DRAM following node reallocation over 17 minutes later. This issue is particularly relevant for systems which support FPGA multi-tenancy.
- Published
- 2024
25. Vector Magnetometry Using Shallow Implanted NV Centers in Diamond with Waveguide-Assisted Dipole Excitation and Readout
- Author
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Shahbazi, Sajedeh, Coccia, Giulio, Lang, Johannes, Bharadwaj, Vibhav, Jelezko, Fedor, Ramponi, Roberta, Bennett, Anthony J., Hadden, John P., Eaton, Shane M., and Kubanek, Alexander
- Subjects
Quantum Physics ,Physics - Optics - Abstract
On-chip magnetic field sensing with Nitrogen-Vacancy (NV) centers in diamond requires scalable integration of 3D waveguides into diamond substrates. Here, we develop a sensing array device with an ensemble of shallow implanted NV centers integrated with arrays of laser-written waveguides for excitation and readout of NV signals. Our approach enables an easy-to-operate on-chip magnetometer with a pixel size proportional to the Gaussian mode area of each waveguide. The performed continuous wave optically detected magnetic resonance on each waveguide gives an average dc-sensitivity value of $195 \pm 3 {nT}/\sqrt{Hz}$, which can be improved with lock-in-detection or pulsed-microwave sequences. We apply a magnetic field to separate the four NV crystallographic orientations of the magnetic resonance and then utilize a DC current through a straight wire antenna close to the waveguide to prove the sensor capabilities of our device. We reconstruct the complete vector magnetic field in the NV crystal frame using three different NV crystallographic orientations. By knowing the polarization axis of the waveguide mode, we project the magnetic field vector into the lab frame.
- Published
- 2024
26. Unraveling Optical Polarization at Deep Microscopic Scales in Crystalline Materials
- Author
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Bharadwaj, Sathwik and Jacob, Zubin
- Subjects
Physics - Optics ,Condensed Matter - Materials Science - Abstract
Nanophotonics, the study of light-matter interaction at scales smaller than the wavelength of radiation, has widespread applications in plasmonic waveguiding, topological photonic crystals, super-lensing, solar absorbers, and infrared imaging. The physical phenomena governing these effects can be described using a macroscopic homogenized refractive index. However, the lattice-level description of optical polarization in a crystalline material using a quantum theory has been unresolved. Inspired by the dynamics of electron waves and their corresponding band structure, we propose a microscopic optical band theory of solids specifically applicable to optical polarization. This framework reveals propagating waves hidden deep within a crystal lattice. These hidden waves arise from crystal-optical-indices, a family of quantum functions obeying crystal symmetries, and cannot be described by the conventional concept of refractive index. We present for the first time - the hidden waves and deep microscopic optical band structure of 14 distinct materials. We choose Si, Ge, InAs, GaAs, CdTe, and others from Group IV, III-V, and II-VI due to their technological relevance but our framework can be extended to a wide range of emerging 2D and 3D materials. In contrast to the macroscopic refractive index of these materials used widely today, this framework shows that hidden waves exist throughout the crystal lattice and have unique optical polarization texture and crowding. We also present an open-source software package, Purdue-Picomax, for the research community to discover hidden waves in new materials like hBN, graphene, and Moire materials. Our work establishes a foundational crystallographic feature to discover novel deep microscopic optical waves in light-matter interaction., Comment: 25 Pages, 6 Figures
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- 2024
27. A Benchmark Dataset for Multimodal Prediction of Enzymatic Function Coupling DNA Sequences and Natural Language
- Author
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Zhang, Yuchen, Jha, Ratish Kumar Chandrakant, Bharadwaj, Soumya, Thakkar, Vatsal Sanjaykumar, Hoarfrost, Adrienne, and Sun, Jin
- Subjects
Quantitative Biology - Genomics ,Computer Science - Machine Learning - Abstract
Predicting gene function from its DNA sequence is a fundamental challenge in biology. Many deep learning models have been proposed to embed DNA sequences and predict their enzymatic function, leveraging information in public databases linking DNA sequences to an enzymatic function label. However, much of the scientific community's knowledge of biological function is not represented in these categorical labels, and is instead captured in unstructured text descriptions of mechanisms, reactions, and enzyme behavior. These descriptions are often captured alongside DNA sequences in biological databases, albeit in an unstructured manner. Deep learning of models predicting enzymatic function are likely to benefit from incorporating this multi-modal data encoding scientific knowledge of biological function. There is, however, no dataset designed for machine learning algorithms to leverage this multi-modal information. Here we propose a novel dataset and benchmark suite that enables the exploration and development of large multi-modal neural network models on gene DNA sequences and natural language descriptions of gene function. We present baseline performance on benchmarks for both unsupervised and supervised tasks that demonstrate the difficulty of this modeling objective, while demonstrating the potential benefit of incorporating multi-modal data types in function prediction compared to DNA sequences alone. Our dataset is at: https://hoarfrost-lab.github.io/BioTalk/.
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- 2024
28. $W-$mass and Muon $g-2$ in Inert 2HDM Extended by Singlet Complex Scalar
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Bharadwaj, Hrishabh, Dahiya, Mamta, Dutta, Sukanta, and Goyal, Ashok
- Subjects
High Energy Physics - Phenomenology - Abstract
The deviations of the recent measurements of the muon magnetic moment and the $W-$boson mass from their SM predictions hint to new physics beyond the SM. In this article, we address the observed discrepancies in the $W$-boson mass and muon anomalous magnetic moment in the Inert Two Higgs Doublet Model (I2HDM) extended by a complex scalar field singlet under the SM gauge group. The model is constrained from the existing LEP data and the measurements of partial decay widths to gauge bosons at LHC. It is shown that a large subset of this constrained parameter space of the model can simultaneously accommodate the $W$-boson mass and also explain the muon $g-2$ anomaly., Comment: 15 pages, 5 figures
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- 2024
29. Galaxy Zoo DESI: large-scale bars as a secular mechanism for triggering AGN
- Author
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Garland, Izzy L., Walmsley, Mike, Silcock, Maddie S., Potts, Leah M., Smith, Josh, Simmons, Brooke D., Lintott, Chris J., Smethurst, Rebecca J., Dawson, James M., Keel, William C., Kruk, Sandor, Mantha, Kameswara Bharadwaj, Masters, Karen L., O'Ryan, David, Popp, Jürgen J., and Thorne, Matthew R.
- Subjects
Astrophysics - Astrophysics of Galaxies ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
Despite the evidence that supermassive black holes (SMBHs) co-evolve with their host galaxy, and that most of the growth of these SMBHs occurs via merger-free processes, the underlying mechanisms which drive this secular co-evolution are poorly understood. We investigate the role that both strong and weak large-scale galactic bars play in mediating this relationship. Using 72,940 disc galaxies in a volume-limited sample from Galaxy Zoo DESI, we analyse the active galactic nucleus (AGN) fraction in strongly barred, weakly barred, and unbarred galaxies up to z = 0.1 over a range of stellar masses and colours. After controlling for stellar mass and colour, we find that the optically selected AGN fraction is 31.6 +/- 0.9 per cent in strongly barred galaxies, 23.3 +/- 0.8 per cent in weakly barred galaxies, and 14.2 +/- 0.6 per cent in unbarred disc galaxies. These are highly statistically robust results, strengthening the tantalising results in earlier works. Strongly barred galaxies have a higher fraction of AGNs than weakly barred galaxies, which in turn have a higher fraction than unbarred galaxies. Thus, while bars are not required in order to grow a SMBH in a disc galaxy, large-scale galactic bars appear to facilitate AGN fuelling, and the presence of a strong bar makes a disc galaxy more than twice as likely to host an AGN than an unbarred galaxy at all galaxy stellar masses and colours., Comment: 11 pages, 8 figures, accepted for publication in MNRAS
- Published
- 2024
30. An Eulerian Meshless Method for Two-phase Flows with Embedded Geometries
- Author
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Bharadwaj, Anand S, Suchde, Pratik, and Nair, Prapanch
- Subjects
Physics - Fluid Dynamics - Abstract
We present a novel Eulerian meshless method for two-phase flows with arbitrary embedded geometries. The spatial derivatives are computed using the meshless generalized finite difference method (GFDM). The sharp phase interface is tracked using a volume fraction function. The volume fraction is advected using a method based on the minimisation of a directional flux-based error. For stability, the advection terms are discretised using upwinding schemes. In the vicinity of the embedded geometries, the signed distance function is used to populate the surface of the geometries to generate a body-conforming point cloud. Consequently, the points on the boundaries participate directly in the discretisation, unlike conventional immersed-boundary methods where they are either used to calculate momentum deficit (for example, continuous forcing) or conservation losses (for example, cut-cell methods). The boundary conditions are, therefore, directly imposed at these points on the embedded geometries, opening up the possibility for a discretisation that is body-conforming and spatially varying in resolution, while retaining the consistency of the scheme. We present benchmark test cases that validate the method for two-phase flows, flows with embedded boundaries and a combination of both.
- Published
- 2024
- Full Text
- View/download PDF
31. Exploring new physics via effective interactions
- Author
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Singh, Ekata, Bharadwaj, Hrishabh, and Devisharan
- Subjects
High Energy Physics - Phenomenology - Abstract
We investigate self-conjugate Dark Matter (DM) particles that primarily interact with standard model electroweak gauge bosons within an effective field theoretical framework. Our analysis focuses on effective contact interactions, invariant under the standard model gauge group, between Majorana fermions, and real scalar DM, with SM neutral electroweak gauge bosons. We calculate the Wilson coefficients for interaction terms up to dimension-8 and establish constraints on the theory's parameters. These constraints are derived from the observed relic density, and indirect detection observations. We discuss the potential for dark matter-nucleon scattering in direct detection experiments. Additionally, we utilize low-energy LEP data to assess sensitivity to the pair production of low-mass ($\leq$ 80 GeV) DM particles. Furthermore, we highlight the potential of the proposed International Linear Collider (ILC) in probing effective operators through the pair production of DM particles with masses $\geq$ 50 GeV in association with mono-photons., Comment: 14 pages, 8 figures
- Published
- 2024
- Full Text
- View/download PDF
32. Block-level Text Spotting with LLMs
- Author
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Bannur, Ganesh and Amrutur, Bharadwaj
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
Text spotting has seen tremendous progress in recent years yielding performant techniques which can extract text at the character, word or line level. However, extracting blocks of text from images (block-level text spotting) is relatively unexplored. Blocks contain more context than individual lines, words or characters and so block-level text spotting would enhance downstream applications, such as translation, which benefit from added context. We propose a novel method, BTS-LLM (Block-level Text Spotting with LLMs), to identify text at the block level. BTS-LLM has three parts: 1) detecting and recognizing text at the line level, 2) grouping lines into blocks and 3) finding the best order of lines within a block using a large language model (LLM). We aim to exploit the strong semantic knowledge in LLMs for accurate block-level text spotting. Consequently if the text spotted is semantically meaningful but has been corrupted during text recognition, the LLM is also able to rectify mistakes in the text and produce a reconstruction of it., Comment: 19 pages, 7 figures
- Published
- 2024
33. VANE-Bench: Video Anomaly Evaluation Benchmark for Conversational LMMs
- Author
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Bharadwaj, Rohit, Gani, Hanan, Naseer, Muzammal, Khan, Fahad Shahbaz, and Khan, Salman
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
The recent developments in Large Multi-modal Video Models (Video-LMMs) have significantly enhanced our ability to interpret and analyze video data. Despite their impressive capabilities, current Video-LMMs have not been evaluated for anomaly detection tasks, which is critical to their deployment in practical scenarios e.g., towards identifying deepfakes, manipulated video content, traffic accidents and crimes. In this paper, we introduce VANE-Bench, a benchmark designed to assess the proficiency of Video-LMMs in detecting and localizing anomalies and inconsistencies in videos. Our dataset comprises an array of videos synthetically generated using existing state-of-the-art text-to-video generation models, encompassing a variety of subtle anomalies and inconsistencies grouped into five categories: unnatural transformations, unnatural appearance, pass-through, disappearance and sudden appearance. Additionally, our benchmark features real-world samples from existing anomaly detection datasets, focusing on crime-related irregularities, atypical pedestrian behavior, and unusual events. The task is structured as a visual question-answering challenge to gauge the models' ability to accurately detect and localize the anomalies within the videos. We evaluate nine existing Video-LMMs, both open and closed sources, on this benchmarking task and find that most of the models encounter difficulties in effectively identifying the subtle anomalies. In conclusion, our research offers significant insights into the current capabilities of Video-LMMs in the realm of anomaly detection, highlighting the importance of our work in evaluating and improving these models for real-world applications. Our code and data is available at https://hananshafi.github.io/vane-benchmark/, Comment: Data: https://huggingface.co/datasets/rohit901/VANE-Bench
- Published
- 2024
34. Efficient Leverage Score Sampling for Tensor Train Decomposition
- Author
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Bharadwaj, Vivek, Rakhshan, Beheshteh T., Malik, Osman Asif, and Rabusseau, Guillaume
- Subjects
Computer Science - Data Structures and Algorithms - Abstract
Tensor Train~(TT) decomposition is widely used in the machine learning and quantum physics communities as a popular tool to efficiently compress high-dimensional tensor data. In this paper, we propose an efficient algorithm to accelerate computing the TT decomposition with the Alternating Least Squares (ALS) algorithm relying on exact leverage scores sampling. For this purpose, we propose a data structure that allows us to efficiently sample from the tensor with time complexity logarithmic in the tensor size. Our contribution specifically leverages the canonical form of the TT decomposition. By maintaining the canonical form through each iteration of ALS, we can efficiently compute (and sample from) the leverage scores, thus achieving significant speed-up in solving each sketched least-square problem. Experiments on synthetic and real data on dense and sparse tensors demonstrate that our method outperforms SVD-based and ALS-based algorithms.
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- 2024
35. Enhancing Vision Models for Text-Heavy Content Understanding and Interaction
- Author
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TG, Adithya, SK, Adithya, Bharadwaj, Abhinav R, HA, Abhiram, and Narayan, Surabhi
- Subjects
Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Artificial Intelligence ,Computer Science - Computation and Language - Abstract
Interacting and understanding with text heavy visual content with multiple images is a major challenge for traditional vision models. This paper is on enhancing vision models' capability to comprehend or understand and learn from images containing a huge amount of textual information from the likes of textbooks and research papers which contain multiple images like graphs, etc and tables in them with different types of axes and scales. The approach involves dataset preprocessing, fine tuning which is by using instructional oriented data and evaluation. We also built a visual chat application integrating CLIP for image encoding and a model from the Massive Text Embedding Benchmark which is developed to consider both textual and visual inputs. An accuracy of 96.71% was obtained. The aim of the project is to increase and also enhance the advance vision models' capabilities in understanding complex visual textual data interconnected data, contributing to multimodal AI., Comment: 5 pages, 4 figures (including 1 graph)
- Published
- 2024
36. S3D: A Simple and Cost-Effective Self-Speculative Decoding Scheme for Low-Memory GPUs
- Author
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Zhong, Wei and Bharadwaj, Manasa
- Subjects
Computer Science - Computation and Language - Abstract
Speculative decoding (SD) has attracted a significant amount of research attention due to the substantial speedup it can achieve for LLM inference. However, despite the high speedups they offer, speculative decoding methods often achieve optimal performance on high-end devices or with a substantial GPU memory overhead. Given limited memory and the necessity of quantization, a high-performing model on a high-end GPU can slow down by up to 7 times. To this end, we propose Skippy Simultaneous Speculative Decoding (or S3D), a cost-effective self-speculative SD method based on simultaneous multi-token decoding and mid-layer skipping. When compared against recent effective open-source SD systems, our method has achieved one of the top performance-memory ratios while requiring minimal architecture changes and training data. Leveraging our memory efficiency, we created a smaller yet more effective SD model based on Phi-3. It is 1.4 to 2 times faster than the quantized EAGLE model and operates in half-precision while using less VRAM.
- Published
- 2024
37. A Brisk Estimator for the Angular Multipoles (BEAM) of the redshift space bispectrum
- Author
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Gill, Sukhdeep Singh and Bharadwaj, Somnath
- Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Astrophysics of Galaxies - Abstract
The anisotropy of the redshift space bispectrum depends upon the orientation of the triangles formed by three $\vec{k}$ modes with respect to the line of sight. For a triangle of fixed size ($k_1$) and shape ($\mu,t$), this orientation dependence can be quantified in terms of angular multipoles $B_l^m(k_1,\mu,t)$ which contain a wealth of cosmological information. We propose a fast and efficient FFT-based estimator that computes bispectrum multipole moments $B_l^m$ of a 3D cosmological field for all possible $l$ and $m$ (including $m\neq 0$). The time required by the estimator to compute all multipoles from a gridded data cube of volume $N_g^3$ scales as $\sim N_g^3 \log{(N_g)}$ in contrast to the direct computation technique which requires time $\sim N_g^6$. Here, we demonstrate the formalism and validate othe estimator using a simulated non-Gaussian field for which the analytical expressions for all bispectrum multipoles are known. The estimated results are found to be in good agreement with the analytical predictions for all $16$ non-zero multipoles (up to $\ell= 6, m=6$). We expect the $m \neq 0$ bispectrum multipoles to significantly enhance the information available from galaxy redshift surveys, and future redshifted 21-cm observations., Comment: Comments are welcome
- Published
- 2024
38. Resurrection Attack: Defeating Xilinx MPU's Memory Protection
- Author
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Madabhushi, Bharadwaj, Mummidi, Chandra Sekhar, Kundu, Sandip, and Holcomb, Daniel
- Subjects
Computer Science - Cryptography and Security - Abstract
Memory protection units (MPUs) are hardware-assisted security features that are commonly used in embedded processors such as the ARM 940T, Infineon TC1775, and Xilinx Zynq. MPUs partition the memory statically, and set individual protection attributes for each partition. MPUs typically define two protection domains: user mode and supervisor mode. Normally, this is sufficient for protecting the kernel and applications. However, we have discovered a way to access a process memory due to a vulnerability in Xilinx MPU (XMPU) implementation that we call Resurrection Attack. We find that XMPU security policy protects user memory from unauthorized access when the user is active. However, when a user's session is terminated, the contents of the memory region of the terminated process are not cleared. An attacker can exploit this vulnerability by gaining access to the memory region after it has been reassigned. The attacker can read the data from the previous user's memory region, thereby compromising the confidentiality. To prevent the Resurrection Attack, the memory region of a terminated process must be cleared. However, this is not the case in the XMPU implementation, which allows our attack to succeed. The Resurrection Attack is a serious security flaw that could be exploited to steal sensitive data or gain unauthorized access to a system. It is important for users of Xilinx FPGAs to be aware of this vulnerability until this flaw is addressed.
- Published
- 2024
39. Memory Scraping Attack on Xilinx FPGAs: Private Data Extraction from Terminated Processes
- Author
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Madabhushi, Bharadwaj, Kundu, Sandip, and Holcomb, Daniel
- Subjects
Computer Science - Cryptography and Security ,Computer Science - Hardware Architecture - Abstract
FPGA-based hardware accelerators are becoming increasingly popular due to their versatility, customizability, energy efficiency, constant latency, and scalability. FPGAs can be tailored to specific algorithms, enabling efficient hardware implementations that effectively leverage algorithm parallelism. This can lead to significant performance improvements over CPUs and GPUs, particularly for highly parallel applications. For example, a recent study found that Stratix 10 FPGAs can achieve up to 90\% of the performance of a TitanX Pascal GPU while consuming less than 50\% of the power. This makes FPGAs an attractive choice for accelerating machine learning (ML) workloads. However, our research finds privacy and security vulnerabilities in existing Xilinx FPGA-based hardware acceleration solutions. These vulnerabilities arise from the lack of memory initialization and insufficient process isolation, which creates potential avenues for unauthorized access to private data used by processes. To illustrate this issue, we conducted experiments using a Xilinx ZCU104 board running the PetaLinux tool from Xilinx. We found that PetaLinux does not effectively clear memory locations associated with a terminated process, leaving them vulnerable to memory scraping attack (MSA). This paper makes two main contributions. The first contribution is an attack methodology of using the Xilinx debugger from a different user space. We find that we are able to access process IDs, virtual address spaces, and pagemaps of one user from a different user space because of lack of adequate process isolation. The second contribution is a methodology for characterizing terminated processes and accessing their private data. We illustrate this on Xilinx ML application library.
- Published
- 2024
40. The Tracking Tapered Gridded Estimator for the 21-cm power spectrum from MWA drift scan observations I: Validation and preliminary results
- Author
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Chatterjee, Suman, Elahi, Khandakar Md Asif, Bharadwaj, Somnath, Sarkar, Shouvik, Choudhuri, Samir, Sethi, Shiv, and Patwa, Akash Kumar
- Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Drift scan observations provide the broad sky coverage and instrumental stability needed to measure the Epoch of Reionization (EoR) 21-cm signal. In such observations, the telescope's pointing center (PC) moves continuously on the sky. The Tracking Tapered Gridded Estimator (TTGE) combines observations from different PC to estimate $P(k_{\perp}, k_{\parallel})$ the 21-cm power spectrum, centered on a tracking center (TC) which remains fixed on the sky. The tapering further restricts the sky response to a small angular region around TC, thereby mitigating wide-field foregrounds. Here we consider $154.2 \, {\rm MHz}$ ($z = 8.2$) Murchison Widefield Array (MWA) drift scan observations. The periodic pattern of flagged channels, present in MWA data, is known to introduce artefacts which pose a challenge for estimating $P(k_{\perp}, k_{\parallel})$. We demonstrate that the TTGE is able to recover $P(k_{\perp}, k_{\parallel})$ without any artefacts, and estimate $P(k)$ within $5 \%$ accuracy over a large $k$-range. We also present preliminary results for a single PC, combining 9 nights of observation $(17 \, {\rm min}$ total). We find that $P(k_{\perp}, k_{\parallel})$ exhibits streaks at a fixed interval of $k_{\parallel}=0.29 \, {\rm Mpc}^{-1}$, which matches $\Delta \nu_{\rm per}=1.28 \, {\rm MHz}$ that is the period of the flagged channels. The streaks are not as pronounced at larger $k_{\parallel}$, and in some cases they do not appear to extend across the entire $k_{\perp}$ range. The rectangular region $0.05 \leq k_{\perp} \leq 0.16 \, {\rm Mpc^{-1}}$ and $0.9 \leq k_{\parallel} \leq 4.6 \, {\rm Mpc^{-1}}$ is found to be relatively free of foreground contamination and artefacts, and we have used this to place the $2\sigma$ upper limit $\Delta^2(k) < (1.85 \times 10^4)^2\, {\rm mK^2}$ on the EoR 21-cm mean squared brightness temperature fluctuations at $k=1 \,{\rm Mpc}^{-1}$., Comment: 15 pages, 11 figures, accepted for publication in PASA
- Published
- 2024
41. Lean Attention: Hardware-Aware Scalable Attention Mechanism for the Decode-Phase of Transformers
- Author
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Sanovar, Rya, Bharadwaj, Srikant, Amant, Renee St., Rühle, Victor, and Rajmohan, Saravan
- Subjects
Computer Science - Hardware Architecture ,Computer Science - Machine Learning ,I.2.7 ,C.1.4 - Abstract
Transformer-based models have emerged as one of the most widely used architectures for natural language processing, natural language generation, and image generation. The size of the state-of-the-art models has increased steadily reaching billions of parameters. These huge models are memory hungry and incur significant inference latency even on cutting edge AI-accelerators, such as GPUs. Specifically, the time and memory complexity of the attention operation is quadratic in terms of the total context length, i.e., prompt and output tokens. Thus, several optimizations such as key-value tensor caching and FlashAttention computation have been proposed to deliver the low latency demands of applications relying on such large models. However, these techniques do not cater to the computationally distinct nature of different phases during inference. To that end, we propose LeanAttention, a scalable technique of computing self-attention for the token-generation phase (decode-phase) of decoder-only transformer models. LeanAttention enables scaling the attention mechanism implementation for the challenging case of long context lengths by re-designing the execution flow for the decode-phase. We identify that the associative property of online softmax can be treated as a reduction operation thus allowing us to parallelize the attention computation over these large context lengths. We extend the "stream-K" style reduction of tiled calculation to self-attention to enable parallel computation resulting in an average of 2.6x attention execution speedup over FlashAttention-2 and up to 8.33x speedup for 512k context lengths., Comment: 13 pages, 10 figures
- Published
- 2024
42. Compact quantum algorithms for time-dependent differential equations
- Author
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Bharadwaj, Sachin S. and Sreenivasan, Katepalli R.
- Subjects
Quantum Physics ,Physics - Applied Physics ,Physics - Computational Physics ,Physics - Fluid Dynamics - Abstract
Many claims of computational advantages have been made for quantum computing over classical, but they have not been demonstrated for practical problems. Here, we present algorithms for solving time-dependent PDEs, with particular reference to fluid equations. We build on an idea based on linear combination of unitaries to simulate non-unitary, non-Hermitian quantum systems, and generate hybrid quantum-classical algorithms that efficiently perform iterative matrix-vector multiplication and matrix inversion operations. Though these algorithms are end-to-end, they require relatively low-depth quantum circuits and protect quantum advantage, with the best-case asymptotic complexities, which we show} are near-optimal. We demonstrate the performance of the algorithms by conducting: (a) fully gate level, state-vector simulations using an in-house, high performance, quantum simulator called QFlowS; (b) experiments on a real quantum device; and (c) noisy simulations using Qiskit Aer. We also provide device specifications such as error-rates (noise) and state sampling (measurement) to accurately perform convergent flow simulations on noisy devices. The results offer evidence that the proposed algorithm is amenable for use on near-term quantum devices., Comment: 31 pages, 10 figures, 1 table
- Published
- 2024
43. A Timely Survey on Vision Transformer for Deepfake Detection
- Author
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Wang, Zhikan, Cheng, Zhongyao, Xiong, Jiajie, Xu, Xun, Li, Tianrui, Veeravalli, Bharadwaj, and Yang, Xulei
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
In recent years, the rapid advancement of deepfake technology has revolutionized content creation, lowering forgery costs while elevating quality. However, this progress brings forth pressing concerns such as infringements on individual rights, national security threats, and risks to public safety. To counter these challenges, various detection methodologies have emerged, with Vision Transformer (ViT)-based approaches showcasing superior performance in generality and efficiency. This survey presents a timely overview of ViT-based deepfake detection models, categorized into standalone, sequential, and parallel architectures. Furthermore, it succinctly delineates the structure and characteristics of each model. By analyzing existing research and addressing future directions, this survey aims to equip researchers with a nuanced understanding of ViT's pivotal role in deepfake detection, serving as a valuable reference for both academic and practical pursuits in this domain.
- Published
- 2024
44. Computational Electromagnetics Meets Spin Qubits: Controlling Noise Effects in Quantum Sensing and Computing
- Author
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Sun, Wenbo, Bharadwaj, Sathwik, Zhou, Runwei, Jiao, Dan, and Jacob, Zubin
- Subjects
Quantum Physics ,Physics - Computational Physics ,Physics - Optics - Abstract
Solid-state spin qubits have emerged as promising platforms for quantum information. Despite extensive efforts in controlling noise in spin qubit quantum applications, one important but less controlled noise source is near-field electromagnetic fluctuations. Low-frequency (MHz and GHz) electromagnetic fluctuations are significantly enhanced near lossy material components in quantum applications, including metallic/superconducting gates necessary for controlling spin qubits in quantum computing devices and materials/nanostructures to be probed in quantum sensing. Although controlling this low-frequency electromagnetic fluctuation noise is crucial for improving the performance of quantum devices, current efforts are hindered by computational challenges. In this paper, we leverage advanced computational electromagnetics techniques, especially fast and accurate volume integral equation based solvers, to overcome the computational obstacle. We introduce a quantum computational electromagnetics framework to control low-frequency magnetic fluctuation noise and enhance spin qubit device performance. Our framework extends the application of computational electromagnetics to spin qubit quantum devices. Furthermore, we demonstrate the application of our framework in realistic quantum devices. Our work paves the way for device engineering to control magnetic fluctuations and improve the performance of spin qubit quantum sensing and computing., Comment: 13 pages, 6 figures
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- 2024
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45. Water Cherenkov muon veto for the COSINUS experiment: design and simulation optimization
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Angloher, G., Bharadwaj, M. R., Cababie, M., Dafinei, I., Di Marco, N., Einfalt, L., Ferroni, F., Fichtinger, S., Filipponi, A., Frank, T., Friedl, M., Ge, Z., Heikinheimo, M., Hughes, M. N., Huitu, K., Kellermann, M., Maji, R., Mancuso, M., Pagnanini, L., Petricca, F., Pirro, S., Pröbst, F., Profeta, G., Puiu, A., Reindl, F., Schäffner, K., Schieck, J., Schmiedmayer, D., Schreiner, P., Schwertner, C., Shera, K., Stahlberg, M., Stendhal, A., Stukel, M., Tresca, C., Wagner, F., Yue, S., Zema, V., and Zhu, Y.
- Subjects
Physics - Instrumentation and Detectors - Abstract
COSINUS is a dark matter (DM) direct search experiment that uses sodium iodide (NaI) crystals as cryogenic calorimeters. Thanks to the low nuclear recoil energy threshold and event-by-event discrimination capability, COSINUS will address the long-standing DM claim made by the DAMA/LIBRA collaboration. The experiment is currently under construction at the Laboratori Nazionali del Gran Sasso, Italy, and employs a large cylindrical water tank as a passive shield to meet the required background rate. However, muon-induced neutrons can mimic a DM signal therefore requiring an active veto system, which is achieved by instrumenting the water tank with an array of photomultiplier tubes (PMTs). This study optimizes the number, arrangement, and trigger conditions of the PMTs as well as the size of an optically invisible region. The objective was to maximize the muon veto efficiency while minimizing the accidental trigger rate due to the ambient and instrumental background. The final configuration predicts a veto efficiency of 99.63 $\pm$ 0.16 $\%$ and 44.4 $\pm$ $5.6\%$ in the tagging of muon events and showers of secondary particles, respectively. The active veto will reduce the cosmogenic neutron background rate to 0.11 $\pm$ 0.02 cts$\cdot$kg$^{-1}$$\cdot$year$^{-1}$, corresponding to less than one background event in the region of interest for the whole COSINUS-1$\pi$ exposure of 1000 kg$\cdot$days.
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- 2024
- Full Text
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46. IndicGenBench: A Multilingual Benchmark to Evaluate Generation Capabilities of LLMs on Indic Languages
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Singh, Harman, Gupta, Nitish, Bharadwaj, Shikhar, Tewari, Dinesh, and Talukdar, Partha
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Computer Science - Computation and Language - Abstract
As large language models (LLMs) see increasing adoption across the globe, it is imperative for LLMs to be representative of the linguistic diversity of the world. India is a linguistically diverse country of 1.4 Billion people. To facilitate research on multilingual LLM evaluation, we release IndicGenBench - the largest benchmark for evaluating LLMs on user-facing generation tasks across a diverse set 29 of Indic languages covering 13 scripts and 4 language families. IndicGenBench is composed of diverse generation tasks like cross-lingual summarization, machine translation, and cross-lingual question answering. IndicGenBench extends existing benchmarks to many Indic languages through human curation providing multi-way parallel evaluation data for many under-represented Indic languages for the first time. We evaluate a wide range of proprietary and open-source LLMs including GPT-3.5, GPT-4, PaLM-2, mT5, Gemma, BLOOM and LLaMA on IndicGenBench in a variety of settings. The largest PaLM-2 models performs the best on most tasks, however, there is a significant performance gap in all languages compared to English showing that further research is needed for the development of more inclusive multilingual language models. IndicGenBench is released at www.github.com/google-research-datasets/indic-gen-bench, Comment: ACL 2024
- Published
- 2024
47. Decade-Bandwidth RF-Input Pseudo-Doherty Load Modulated Balanced Amplifier using Signal-Flow-Based Phase Alignment Design
- Author
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Gong, Pingzhu, Guo, Jiachen, Vangipurapu, Niteesh Bharadwaj, and Chen, Kenle
- Subjects
Computer Science - Hardware Architecture ,Electrical Engineering and Systems Science - Signal Processing - Abstract
This paper reports a first-ever decade-bandwidth pseudo-Doherty load-modulated balanced amplifier (PD-LMBA), designed for emerging 4G/5G communications and multi-band operations. By revisiting the LMBA theory using the signal-flow graph, a frequency-agnostic phase-alignment condition is found that is critical for ensuring intrinsically broadband load modulation behavior. This unique design methodology enables, for the first time, the independent optimization of broadband balanced amplifier (BA, as the peaking) and control amplifier (CA, as the carrier), thus fundamentally addressing the longstanding limits imposed on the design of wideband load-modulated power amplifiers (PAs). To prove the proposed concept, an ultra-wideband RF-input PD-LMBA is designed and developed using GaN technology covering the frequency range from 0.2 to 2 GHz. Experimental results demonstrate an efficiency of 51% to 72% for peak output power and 44% to 62% for 10-dB OBO, respectively., Comment: This paper has been accepted for publication by IEEE Microwave and Wireless Technology Letters (not published). The IEEE copyright receipt is attached
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- 2024
48. Unlocking Quantum Optimization: A Use Case Study on NISQ Systems
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Sturm, Andreas, Mummaneni, Bharadwaj, and Rullkötter, Leon
- Subjects
Quantum Physics - Abstract
The major advances in quantum computing over the last few decades have sparked great interest in applying it to solve the most challenging computational problems in a wide variety of areas. One of the most pronounced domains here are optimization problems and a number of algorithmic approaches have been proposed for their solution. For the current noisy intermediate-scale quantum (NISQ) computers the quantum approximate optimization algorithm (QAOA), the variational quantum eigensolver (VQE), and quantum annealing (QA) are the central algorithms for this problem class. The two former can be executed on digital gate-model quantum computers, whereas the latter requires a quantum annealer. Across all hardware architectures and manufactures, the quantum computers available today share the property of being too error-prone to reliably execute involved quantum circuits as they typically arise from quantum optimization algorithms. In order to characterize the limits of existing quantum computers, many component and system level benchmarks have been proposed. However, owing to the complex nature of the errors in quantum systems these benchmark fail to provide predictive power beyond simple quantum circuits and small examples. Application oriented benchmarks have been proposed to remedy this problem, but both, results from real quantum systems as well as use cases beyond constructed academic examples, remain very rare. This paper addresses precisely this gap by considering two industrial relevant use cases: one in the realm of optimizing charging schedules for electric vehicles, the other concerned with the optimization of truck routes. Our central contribution are systematic series of examples derived from these uses cases that we execute on different processors of the gate-based quantum computers of IBM as well as on the quantum annealer of D-Wave.
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- 2024
49. DreamScene360: Unconstrained Text-to-3D Scene Generation with Panoramic Gaussian Splatting
- Author
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Zhou, Shijie, Fan, Zhiwen, Xu, Dejia, Chang, Haoran, Chari, Pradyumna, Bharadwaj, Tejas, You, Suya, Wang, Zhangyang, and Kadambi, Achuta
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Artificial Intelligence - Abstract
The increasing demand for virtual reality applications has highlighted the significance of crafting immersive 3D assets. We present a text-to-3D 360$^{\circ}$ scene generation pipeline that facilitates the creation of comprehensive 360$^{\circ}$ scenes for in-the-wild environments in a matter of minutes. Our approach utilizes the generative power of a 2D diffusion model and prompt self-refinement to create a high-quality and globally coherent panoramic image. This image acts as a preliminary "flat" (2D) scene representation. Subsequently, it is lifted into 3D Gaussians, employing splatting techniques to enable real-time exploration. To produce consistent 3D geometry, our pipeline constructs a spatially coherent structure by aligning the 2D monocular depth into a globally optimized point cloud. This point cloud serves as the initial state for the centroids of 3D Gaussians. In order to address invisible issues inherent in single-view inputs, we impose semantic and geometric constraints on both synthesized and input camera views as regularizations. These guide the optimization of Gaussians, aiding in the reconstruction of unseen regions. In summary, our method offers a globally consistent 3D scene within a 360$^{\circ}$ perspective, providing an enhanced immersive experience over existing techniques. Project website at: http://dreamscene360.github.io/
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- 2024
50. A Lagrangian meshfree model for solidification of liquid thin-films
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Bharadwaj, Anand S, Thiel, Elisa, and Suchde, Pratik
- Subjects
Physics - Fluid Dynamics ,Physics - Computational Physics - Abstract
In this paper, a new method to model solidification of thin liquid films is proposed. \blue{This method is targeted at applications like aircraft icing and tablet coating where the formation of liquid films from impinging droplets on a surface form a critical part of the physics of the process.} The proposed model takes into account the (i) unsteadiness in temperature distribution, (ii) heat transfer at the interface between the solid and the surface, (iii) volumetric expansion/contraction and (iv) the liquid thin-film behaviour, each of which are either partly or fully ignored in existing models. The liquid thin-film, modeled using the Discrete Droplet Method (DDM), is represented as a collection of discrete droplets that are tracked in a Lagrangian sense. The height of the liquid film is estimated as a summation of Gaussian kernel functions associated with each droplet. At each droplet location, a solid height is also computed. The evolution of the solid height is governed by the Stefan problem. The flow of the liquid thin-film is solved just as in the case of DDM, while also taking into consideration the shape of the solidified region lying beneath the droplet. The results presented in this work show the reliability of the proposed model in simulating solidification of thin-films and its applicability to complex problems such as ice-formation on aircraft wings. The model has been verified for canonical problems that have analytical solutions. For the more complex problems of icing, the results of the model are compared with data from literature, without considering a background air flow. The comparison can be improved by coupling this model with suitable air flow solvers, as shown in the final test case., Comment: Pre-proof version
- Published
- 2024
- Full Text
- View/download PDF
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