112,687 results on '"Kaushik, A."'
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2. Content analysis of top fifty engineering and technology Universities Library websites in the world
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Kaushik, A.
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- 2022
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3. iNeMo: Incremental Neural Mesh Models for Robust Class-Incremental Learning
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Fischer, Tom, Liu, Yaoyao, Jesslen, Artur, Ahmed, Noor, Kaushik, Prakhar, Wang, Angtian, Yuille, Alan, Kortylewski, Adam, and Ilg, Eddy
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Machine Learning - Abstract
Different from human nature, it is still common practice today for vision tasks to train deep learning models only initially and on fixed datasets. A variety of approaches have recently addressed handling continual data streams. However, extending these methods to manage out-of-distribution (OOD) scenarios has not effectively been investigated. On the other hand, it has recently been shown that non-continual neural mesh models exhibit strong performance in generalizing to such OOD scenarios. To leverage this decisive property in a continual learning setting, we propose incremental neural mesh models that can be extended with new meshes over time. In addition, we present a latent space initialization strategy that enables us to allocate feature space for future unseen classes in advance and a positional regularization term that forces the features of the different classes to consistently stay in respective latent space regions. We demonstrate the effectiveness of our method through extensive experiments on the Pascal3D and ObjectNet3D datasets and show that our approach outperforms the baselines for classification by $2-6\%$ in the in-domain and by $6-50\%$ in the OOD setting. Our work also presents the first incremental learning approach for pose estimation. Our code and model can be found at https://github.com/Fischer-Tom/iNeMo.
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- 2024
4. A Hybrid Spiking-Convolutional Neural Network Approach for Advancing Machine Learning Models
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Sanaullah, Roy, Kaushik, Rückert, Ulrich, and Jungeblut, Thorsten
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Computer Science - Neural and Evolutionary Computing ,Computer Science - Artificial Intelligence - Abstract
In this article, we propose a novel standalone hybrid Spiking-Convolutional Neural Network (SC-NN) model and test on using image inpainting tasks. Our approach uses the unique capabilities of SNNs, such as event-based computation and temporal processing, along with the strong representation learning abilities of CNNs, to generate high-quality inpainted images. The model is trained on a custom dataset specifically designed for image inpainting, where missing regions are created using masks. The hybrid model consists of SNNConv2d layers and traditional CNN layers. The SNNConv2d layers implement the leaky integrate-and-fire (LIF) neuron model, capturing spiking behavior, while the CNN layers capture spatial features. In this study, a mean squared error (MSE) loss function demonstrates the training process, where a training loss value of 0.015, indicates accurate performance on the training set and the model achieved a validation loss value as low as 0.0017 on the testing set. Furthermore, extensive experimental results demonstrate state-of-the-art performance, showcasing the potential of integrating temporal dynamics and feature extraction in a single network for image inpainting., Comment: 7 Pages, 3 figures, and 2 tables
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- 2024
5. GAURA: Generalizable Approach for Unified Restoration and Rendering of Arbitrary Views
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Gupta, Vinayak, Girish, Rongali Simhachala Venkata, T, Mukund Varma, Tewari, Ayush, and Mitra, Kaushik
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Computer Science - Computer Vision and Pattern Recognition - Abstract
Neural rendering methods can achieve near-photorealistic image synthesis of scenes from posed input images. However, when the images are imperfect, e.g., captured in very low-light conditions, state-of-the-art methods fail to reconstruct high-quality 3D scenes. Recent approaches have tried to address this limitation by modeling various degradation processes in the image formation model; however, this limits them to specific image degradations. In this paper, we propose a generalizable neural rendering method that can perform high-fidelity novel view synthesis under several degradations. Our method, GAURA, is learning-based and does not require any test-time scene-specific optimization. It is trained on a synthetic dataset that includes several degradation types. GAURA outperforms state-of-the-art methods on several benchmarks for low-light enhancement, dehazing, deraining, and on-par for motion deblurring. Further, our model can be efficiently fine-tuned to any new incoming degradation using minimal data. We thus demonstrate adaptation results on two unseen degradations, desnowing and removing defocus blur. Code and video results are available at vinayak-vg.github.io/GAURA., Comment: European Conference on Computer Vision(ECCV) 2024
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- 2024
6. Distributed multi-robot potential-field-based exploration with submap-based mapping and noise-augmented strategy
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Pongsirijinda, Khattiya, Cao, Zhiqiang, Bhowmik, Kaushik, Shalihan, Muhammad, Lau, Billy Pik Lik, Liu, Ran, Yuen, Chau, and Tan, U-Xuan
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Computer Science - Robotics - Abstract
Multi-robot collaboration has become a needed component in unknown environment exploration due to its ability to accomplish various challenging situations. Potential-field-based methods are widely used for autonomous exploration because of their high efficiency and low travel cost. However, exploration speed and collaboration ability are still challenging topics. Therefore, we propose a Distributed Multi-Robot Potential-Field-Based Exploration (DMPF-Explore). In particular, we first present a Distributed Submap-Based Multi-Robot Collaborative Mapping Method (DSMC-Map), which can efficiently estimate the robot trajectories and construct the global map by merging the local maps from each robot. Second, we introduce a Potential-Field-Based Exploration Strategy Augmented with Modified Wave-Front Distance and Colored Noises (MWF-CN), in which the accessible frontier neighborhood is extended, and the colored noise provokes the enhancement of exploration performance. The proposed exploration method is deployed for simulation and real-world scenarios. The results show that our approach outperforms the existing ones regarding exploration speed and collaboration ability., Comment: This paper has been accepted by Robotics and Autonomous Systems
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- 2024
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7. Automated and Continuous Chronotyping from a Calendar using Machine Learning
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Kaushik, Pratiik, Askari, Koorosh, Gupta, Saksham, Mohan, Rahul, Skrinak, Kris, Kamyar, Royan, and Smarr, Benjamin
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Quantitative Biology - Other Quantitative Biology - Abstract
Objectives: Chronotypes -- comparisons of individuals' circadian phase relative to others -- can contextualize mental health risk assessments, and support detection of social jet lag, which can hamper mental health and cognition. Existing ways of determining chronotypes, such as Dim Light Melatonin Onset (DLMO) or the Morningness-Eveningness Questionnaire (MEQ), are limited by being discrete in time and time-intensive to update, rarely capturing real-world variability over time. Chronotyping users based on living schedules, as in daily planner apps, might augment existing methods by assessing chronotype and social jet lag continuously and at scale. Developing this functionality would require a novel tool to translate between digital schedules and chronotypes. Here we use a supervised binary classifier to assess the feasibility of this approach. Methods: In this study, 1,460 registered users from the Owaves app opted in to filled out the MEQ survey. Of those, 142 met the eligibility criteria for data analysis. We used multimodal app data to assess the classification of individuals identified as morning and evening types from MEQ data, basing the classifier on app time series data. This includes daily timing for 8 main lifestyle activity categories (exercise, sleep, social interactions, meal times, relaxation, work, play, and miscellaneous) as defined in the app. Results: The novel chronotyping tool was able to predict the morningness and eveningness of its users with an ROC AUC of 0.70. Conclusion: Our findings support the feasibility of chronotype classification from multimodal, real-world app data. We highlight challenges to applying binary labels to complex, multimodal behaviors. Our findings suggest a potential for real-time monitoring to support future, prospective mental health research., Comment: 15 pages, 4 figures, unsubmitted for peer review at date of posting
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- 2024
8. Bidding Games with Charging
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Avni, Guy, Goharshady, Ehsan Kafshdar, Henzinger, Thomas A., and Mallik, Kaushik
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Computer Science - Computer Science and Game Theory - Abstract
Graph games lie at the algorithmic core of many automated design problems in computer science. These are games usually played between two players on a given graph, where the players keep moving a token along the edges according to pre-determined rules, and the winner is decided based on the infinite path traversed by the token from a given initial position. In bidding games, the players initially get some monetary budgets which they need to use to bid for the privilege of moving the token at each step. Each round of bidding affects the players' available budgets, which is the only form of update that the budgets experience. We introduce bidding games with charging where the players can additionally improve their budgets during the game by collecting vertex-dependent charges. Unlike traditional bidding games (where all charges are zero), bidding games with charging allow non-trivial recurrent behaviors. We show that the central property of traditional bidding games generalizes to bidding games with charging: For each vertex there exists a threshold ratio, which is the necessary and sufficient fraction of the total budget for winning the game from that vertex. While the thresholds of traditional bidding games correspond to unique fixed points of linear systems of equations, in games with charging, these fixed points are no longer unique. This significantly complicates the proof of existence and the algorithmic computation of thresholds for infinite-duration objectives. We also provide the lower complexity bounds for computing thresholds for Rabin and Streett objectives, which are the first known lower bounds in any form of bidding games (with or without charging), and we solve the following repair problem for safety and reachability games that have unsatisfiable objectives: Can we distribute a given amount of charge to the players in a way such that the objective can be satisfied?
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- 2024
9. Roadmap to Neuromorphic Computing with Emerging Technologies
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Mehonic, Adnan, Ielmini, Daniele, Roy, Kaushik, Mutlu, Onur, Kvatinsky, Shahar, Serrano-Gotarredona, Teresa, Linares-Barranco, Bernabe, Spiga, Sabina, Savelev, Sergey, Balanov, Alexander G, Chawla, Nitin, Desoli, Giuseppe, Malavena, Gerardo, Compagnoni, Christian Monzio, Wang, Zhongrui, Yang, J Joshua, Syed, Ghazi Sarwat, Sebastian, Abu, Mikolajick, Thomas, Noheda, Beatriz, Slesazeck, Stefan, Dieny, Bernard, Tuo-Hung, Hou, Varri, Akhil, Bruckerhoff-Pluckelmann, Frank, Pernice, Wolfram, Zhang, Xixiang, Pazos, Sebastian, Lanza, Mario, Wiefels, Stefan, Dittmann, Regina, Ng, Wing H, Buckwell, Mark, Cox, Horatio RJ, Mannion, Daniel J, Kenyon, Anthony J, Lu, Yingming, Yang, Yuchao, Querlioz, Damien, Hutin, Louis, Vianello, Elisa, Chowdhury, Sayeed Shafayet, Mannocci, Piergiulio, Cai, Yimao, Sun, Zhong, Pedretti, Giacomo, Strachan, John Paul, Strukov, Dmitri, Gallo, Manuel Le, Ambrogio, Stefano, Valov, Ilia, and Waser, Rainer
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Electrical Engineering and Systems Science - Signal Processing ,Computer Science - Hardware Architecture ,Electrical Engineering and Systems Science - Systems and Control - Abstract
The roadmap is organized into several thematic sections, outlining current computing challenges, discussing the neuromorphic computing approach, analyzing mature and currently utilized technologies, providing an overview of emerging technologies, addressing material challenges, exploring novel computing concepts, and finally examining the maturity level of emerging technologies while determining the next essential steps for their advancement., Comment: 90 pages, 22 figures, roadmap, neuromorphic
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- 2024
10. Non-Terrestrial Networks for 6G: Integrated, Intelligent and Ubiquitous Connectivity
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Jamshed, Muhammad Ali, Kaushik, Aryan, Dajer, Miguel, Guidotti, Alessandro, Parzysz, Fanny, Lagunas, Eva, Di Renzo, Marco, Chatzinotas, Symeon, and Dobre, Octavia A.
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Computer Science - Networking and Internet Architecture ,Electrical Engineering and Systems Science - Signal Processing - Abstract
Universal connectivity has been part of past and current generations of wireless systems, but as we approach 6G, the subject of social responsibility is being built as a core component. Given the advent of Non-Terrestrial Networks (NTN), reaching these goals will be much closer to realization than ever before. Owing to the benefits of NTN, the integration NTN and Terrestrial Networks (TN) is still infancy, where the past, the current and the future releases in the 3$^{\text{rd}}$ Generation Partnership Project (3GPP) provide guidelines to adopt a successfully co-existence/integration of TN and NTN. Therefore, in this article, we have illustrated through 3GPP guidelines, on how NTN and TN can effectively be integrated. Moreover, the role of beamforming and Artificial Intelligence (AI) algorithms is highlighted to achieve this integration. Finally the usefulness of integrating NTN and TN is validated through experimental analysis., Comment: submitted to IEEE Vehicular Technology Magazine
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- 2024
11. Magnetic critical phenomena and low temperature re-entrant spin-glass features of Al$_2$MnFe Heusler alloy
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Khorwal, Abhinav Kumar, Saha, Sujoy, Verma, Mukesh, Saini, Lalita, Kaushik, Suvigya, Bitla, Yugandhar, Lukoyanov, Alexey V., and Patra, Ajit K.
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Condensed Matter - Materials Science - Abstract
A detailed investigation of the structural and magnetic properties, including magnetocaloric effect, re-entrant spin-glass behavior at low temperature, and critical behavior in polycrystalline Al$_2$MnFe Heusler alloy is reported. The prepared alloy crystallizes in a cubic CsCl-type crystal structure with Pm-3m space group. The temperature-dependent magnetization data reveals a second-order paramagnetic to ferromagnetic phase transition ($\sim$ 122.9 K), which is further supported by the analysis of the magnetocaloric effect. The isothermal magnetization loops show a soft ferromagnetic behavior of the studied alloy and also reveal an itinerant character of the underlying exchange interactions. In order to understand the nature of magnetic interactions, the critical exponents for spontaneous magnetization, initial magnetic susceptibility, and critical MH isotherm are determined using Modified Arrott plots, Kouvel-Fisher plots, and critical isotherm analysis. The derived critical exponents $\beta$ = 0.363(2), $\gamma$ = 1.384(3), and $\delta$ = 4.81(3) confirm the critical behavior similar to that of a 3D-Heisenberg-type ferromagnet with short-range exchange interactions that are found to decay with distance as J(r) $\approx$ r$^{-4.936}$. Moreover, the detailed analysis of the AC susceptibility data suggests that the frequency-dependent shifting of the peak temperatures is well explained using standard dynamic scaling laws such as the critical slowing down model and Vogel-Fulcher law, and confirms the signature of re-entrant spin-glass features in Al$_2$MnFe Heusler alloy. Furthermore, maximum magnetic entropy change of $\sim$ 1.92 J/kg-K and relative cooling power of $\sim$ 496 J/kg at 50 kOe applied magnetic field are determined from magnetocaloric studies that are comparable to those of other Mn-Fe-Al systems., Comment: 13 pages (main manuscript), 3 pages (supplementary material), 6 figures (main manuscript), 3 figures (supplementary material), 2 tables (main manuscript)
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- 2024
12. Curvature Clues: Decoding Deep Learning Privacy with Input Loss Curvature
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Ravikumar, Deepak, Soufleri, Efstathia, and Roy, Kaushik
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Computer Science - Machine Learning ,Computer Science - Cryptography and Security - Abstract
In this paper, we explore the properties of loss curvature with respect to input data in deep neural networks. Curvature of loss with respect to input (termed input loss curvature) is the trace of the Hessian of the loss with respect to the input. We investigate how input loss curvature varies between train and test sets, and its implications for train-test distinguishability. We develop a theoretical framework that derives an upper bound on the train-test distinguishability based on privacy and the size of the training set. This novel insight fuels the development of a new black box membership inference attack utilizing input loss curvature. We validate our theoretical findings through experiments in computer vision classification tasks, demonstrating that input loss curvature surpasses existing methods in membership inference effectiveness. Our analysis highlights how the performance of membership inference attack (MIA) methods varies with the size of the training set, showing that curvature-based MIA outperforms other methods on sufficiently large datasets. This condition is often met by real datasets, as demonstrated by our results on CIFAR10, CIFAR100, and ImageNet. These findings not only advance our understanding of deep neural network behavior but also improve the ability to test privacy-preserving techniques in machine learning.
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- 2024
13. Advancing Compressed Video Action Recognition through Progressive Knowledge Distillation
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Soufleri, Efstathia, Ravikumar, Deepak, and Roy, Kaushik
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Machine Learning - Abstract
Compressed video action recognition classifies video samples by leveraging the different modalities in compressed videos, namely motion vectors, residuals, and intra-frames. For this purpose, three neural networks are deployed, each dedicated to processing one modality. Our observations indicate that the network processing intra-frames tend to converge to a flatter minimum than the network processing residuals, which in turn converges to a flatter minimum than the motion vector network. This hierarchy in convergence motivates our strategy for knowledge transfer among modalities to achieve flatter minima, which are generally associated with better generalization. With this insight, we propose Progressive Knowledge Distillation (PKD), a technique that incrementally transfers knowledge across the modalities. This method involves attaching early exits (Internal Classifiers - ICs) to the three networks. PKD distills knowledge starting from the motion vector network, followed by the residual, and finally, the intra-frame network, sequentially improving IC accuracy. Further, we propose the Weighted Inference with Scaled Ensemble (WISE), which combines outputs from the ICs using learned weights, boosting accuracy during inference. Our experiments demonstrate the effectiveness of training the ICs with PKD compared to standard cross-entropy-based training, showing IC accuracy improvements of up to 5.87% and 11.42% on the UCF-101 and HMDB-51 datasets, respectively. Additionally, WISE improves accuracy by up to 4.28% and 9.30% on UCF-101 and HMDB-51, respectively.
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- 2024
14. Multi-State-Action Tokenisation in Decision Transformers for Multi-Discrete Action Spaces
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Moodley, Perusha, Kaushik, Pramod, Thambi, Dhillu, Trovinger, Mark, Paruchuri, Praveen, Hong, Xia, and Rosman, Benjamin
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Computer Science - Machine Learning ,Computer Science - Computer Vision and Pattern Recognition - Abstract
Decision Transformers, in their vanilla form, struggle to perform on image-based environments with multi-discrete action spaces. Although enhanced Decision Transformer architectures have been developed to improve performance, these methods have not specifically addressed this problem of multi-discrete action spaces which hampers existing Decision Transformer architectures from learning good representations. To mitigate this, we propose Multi-State Action Tokenisation (M-SAT), an approach for tokenising actions in multi-discrete action spaces that enhances the model's performance in such environments. Our approach involves two key changes: disentangling actions to the individual action level and tokenising the actions with auxiliary state information. These two key changes also improve individual action level interpretability and visibility within the attention layers. We demonstrate the performance gains of M-SAT on challenging ViZDoom environments with multi-discrete action spaces and image-based state spaces, including the Deadly Corridor and My Way Home scenarios, where M-SAT outperforms the baseline Decision Transformer without any additional data or heavy computational overheads. Additionally, we find that removing positional encoding does not adversely affect M-SAT's performance and, in some cases, even improves it.
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- 2024
15. Real-Time Neuromorphic Navigation: Integrating Event-Based Vision and Physics-Driven Planning on a Parrot Bebop2 Quadrotor
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Joshi, Amogh, Sanyal, Sourav, and Roy, Kaushik
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Computer Science - Robotics - Abstract
In autonomous aerial navigation, real-time and energy-efficient obstacle avoidance remains a significant challenge, especially in dynamic and complex indoor environments. This work presents a novel integration of neuromorphic event cameras with physics-driven planning algorithms implemented on a Parrot Bebop2 quadrotor. Neuromorphic event cameras, characterized by their high dynamic range and low latency, offer significant advantages over traditional frame-based systems, particularly in poor lighting conditions or during high-speed maneuvers. We use a DVS camera with a shallow Spiking Neural Network (SNN) for event-based object detection of a moving ring in real-time in an indoor lab. Further, we enhance drone control with physics-guided empirical knowledge inside a neural network training mechanism, to predict energy-efficient flight paths to fly through the moving ring. This integration results in a real-time, low-latency navigation system capable of dynamically responding to environmental changes while minimizing energy consumption. We detail our hardware setup, control loop, and modifications necessary for real-world applications, including the challenges of sensor integration without burdening the flight capabilities. Experimental results demonstrate the effectiveness of our approach in achieving robust, collision-free, and energy-efficient flight paths, showcasing the potential of neuromorphic vision and physics-driven planning in enhancing autonomous navigation systems.
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- 2024
16. Nonuniqueness in Defining the Polarization: Nonlocal Surface Charges and the Electrostatic, Energetic, and Transport Perspectives
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Sen, Shoham, Wang, Yang, Breitzman, Timothy, and Dayal, Kaushik
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Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
Ionic crystals play a central role in functional applications. Mesoscale descriptions of these crystals are based on the continuum polarization density field to represent the effective physics of charge distribution at the scale of the atomic lattice. However, a long-standing difficulty is that the classical electrostatic definition of the macroscopic polarization -- as the dipole or first moment of the charge density in a unit cell -- is not unique. This unphysical non-uniqueness has been shown to arise from starting directly with an infinite system rather than starting with a finite body and taking appropriate limits. This limit process shows that the electrostatic description requires not only the bulk polarization density, but also the surface charge density, as the effective macroscopic descriptors; that is, a nonlocal effective description. Other approaches to resolve this difficulty include relating the change in polarization to the transport of charge; or, to define the polarization as the energy-conjugate to the electric field. This work examines the relation between the classical electrostatic definition of polarization, and the transport and energy-conjugate definitions of polarization. We show the following: (1) The transport of charge does not correspond to the change in polarization in general; instead, one requires additional simplifying assumptions on the electrostatic definition of polarization for these approaches to give rise to the same macroscopic electric fields. Thus, the electrostatic definition encompasses the transport definition as a special case. (2) The energy-conjugate definition has both bulk and surface contributions; while traditional approaches neglect the surface contribution, we find that accounting for the nonlocal surface contributions is essential to obtain the correct macroscopic electric fields., Comment: Accepted to appear in Journal of the Mechanics and Physics of Solids
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- 2024
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17. Spatial Multiplexing in Near-Field Line-of-Sight MIMO Communications: Paraxial and Non-Paraxial Deployments
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Ruiz-Sicilia, Juan Carlos, Di Renzo, Marco, Mursia, Placido, Kaushik, Aryan, and Sciancalepore, Vincenzo
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Computer Science - Information Theory ,Electrical Engineering and Systems Science - Signal Processing - Abstract
Sixth generation (6G) wireless networks are envisioned to include aspects of energy footprint reduction (sustainability), besides those of network capacity and connectivity, at the design stage. This paradigm change requires radically new physical layer technologies. Notably, the integration of large-aperture arrays and the transmission over high frequency bands, such as the sub-terahertz spectrum, are two promising options. In many communication scenarios of practical interest, the use of large antenna arrays in the sub-terahertz frequency range often results in short-range transmission distances that are characterized by line-of-sight channels, in which pairs of transmitters and receivers are located in the (radiating) near field of one another. These features make the traditional designs, based on the far-field approximation, for multiple-input multiple-output (MIMO) systems sub-optimal in terms of spatial multiplexing gains. To overcome these limitations, new designs for MIMO systems are required, which account for the spherical wavefront that characterizes the electromagnetic waves in the near field, in order to ensure the highest spatial multiplexing gain without increasing the power expenditure. In this paper, we introduce an analytical framework for optimizing the deployment of antenna arrays in line-of-sight channels, which can be applied to paraxial and non-paraxial network deployments. In the paraxial setting, we devise a simpler analytical framework, which, compared to those available in the literature, provides explicit information about the impact of key design parameters. In the non-paraxial setting, we introduce a novel analytical framework that allows us to identify a set of sufficient conditions to be fulfilled for achieving the highest spatial multiplexing gain. The proposed designs are validated with numerical simulations., Comment: This work has been accepted in IEEE Transactions on Green Communications and Networking
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- 2024
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18. CmWave and Sub-THz: Key Radio Enablers and Complementary Spectrum for 6G
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Katwe, Mayur V., Kaushik, Aryan, Singh, Keshav, Di Renzo, Marco, Sun, Shu, Lee, Doohwan, Armada, Ana G., Eldar, Yonina C., Dobre, Octavia A., and Rappaport, Theodore S.
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Electrical Engineering and Systems Science - Signal Processing - Abstract
Sixth-generation (6G) networks are poised to revolutionize communication by exploring alternative spectrum options, aiming to capitalize on strengths while mitigating limitations in current fifth-generation (5G) spectrum. This paper explores the potential opportunities and emerging trends for cmWave and sub-THz spectra as key radio enablers. This paper poses and answers three key questions regarding motivation of additional spectrum to explore the strategic implementation and benefits of cmWave and sub-THz spectra. Also, we show using case studies how these complementary spectrum bands will enable new applications in 6G, such as integrated sensing and communication (ISAC), re-configurable intelligent surfaces (RIS) and non-terrestrial networks (NTN). Numerical simulations reveal that the ISAC performance of cmWave and sub-THz spectra outperforms that of existing 5G spectrum, including sub-6 GHz and mmWave. Additionally, we illustrate the effective interplay between RIS and NTN to counteract the effects of high attenuation at sub-THz frequencies. Finally, ongoing standardization endeavors, challenges and promising directions are elucidated for these complementary spectrum bands.
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- 2024
19. Interpreting the Spectro-Temporal Properties of the Black Hole Candidate Swift J151857.0-572147 during its First Outburst in 2024
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Chatterjee, Kaushik, Suribhatla, S. Pujitha, Mondal, Santanu, and Singh, Chandra B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
For the first time, in March 2024, the transient Galactic black hole candidate Swift J151857.0-572147 experienced an outburst. Using publicly available archived {\it Insight}-HXMT data, we analyze the timing and spectral features of this source. Through model fitting of the power density spectrum, we were able to extract the properties of quasi-periodic oscillations, and based on those properties, we have determined that the QPOs are of type C. We also conclude that the shock instabilities in the transonic advective accretion processes surrounding black holes may be the source of the QPOs. This shock instability could produce variabilities of flux up to 48 keV, as we checked from the QPO energy dependence. High-frequency QPO is not observed during this period. In the broad energy band of $2-100$ keV, simultaneous data from the three on-board instruments of \textit{Insight}-HXMT were used to perform the spectral analysis. A combination of models, including broken power-law, multi-color disk-blackbody continuum, interstellar absorption, and reflection in both neutral and ionized medium were needed for spectral fitting to obtain the best fit. We discovered that at the beginning of the analysis period, the source was in an intermediate state and was transitioning toward the softer states based on the spectral features. It has a hydrogen column density of $(4.3-6.9) \times 10^{22}$ cm$^{-2}$., Comment: 23 pages (1 page Appendix), 14 figures, 7 tables
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- 2024
20. Automatic AI Model Selection for Wireless Systems: Online Learning via Digital Twinning
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Hou, Qiushuo, Zecchin, Matteo, Park, Sangwoo, Cai, Yunlong, Yu, Guanding, Chowdhury, Kaushik, and Simeone, Osvaldo
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Computer Science - Machine Learning ,Computer Science - Information Theory ,Computer Science - Networking and Internet Architecture ,Electrical Engineering and Systems Science - Signal Processing - Abstract
In modern wireless network architectures, such as O-RAN, artificial intelligence (AI)-based applications are deployed at intelligent controllers to carry out functionalities like scheduling or power control. The AI "apps" are selected on the basis of contextual information such as network conditions, topology, traffic statistics, and design goals. The mapping between context and AI model parameters is ideally done in a zero-shot fashion via an automatic model selection (AMS) mapping that leverages only contextual information without requiring any current data. This paper introduces a general methodology for the online optimization of AMS mappings. Optimizing an AMS mapping is challenging, as it requires exposure to data collected from many different contexts. Therefore, if carried out online, this initial optimization phase would be extremely time consuming. A possible solution is to leverage a digital twin of the physical system to generate synthetic data from multiple simulated contexts. However, given that the simulator at the digital twin is imperfect, a direct use of simulated data for the optimization of the AMS mapping would yield poor performance when tested in the real system. This paper proposes a novel method for the online optimization of AMS mapping that corrects for the bias of the simulator by means of limited real data collected from the physical system. Experimental results for a graph neural network-based power control app demonstrate the significant advantages of the proposed approach., Comment: submitted for a journal publication
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- 2024
21. Capture Point Control in Thruster-Assisted Bipedal Locomotion
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Pitroda, Shreyansh, Bondada, Aditya, Krishnamurthy, Kaushik Venkatesh, Salagame, Adarsh, Wang, Chenghao, Liu, Taoran, Gupta, Bibek, Sihite, Eric, Nemovi, Reza, Ramezani, Alireza, and Gharib, Morteza
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Computer Science - Robotics ,Electrical Engineering and Systems Science - Systems and Control - Abstract
Despite major advancements in control design that are robust to unplanned disturbances, bipedal robots are still susceptible to falling over and struggle to negotiate rough terrains. By utilizing thrusters in our bipedal robot, we can perform additional posture manipulation and expand the modes of locomotion to enhance the robot's stability and ability to negotiate rough and difficult-to-navigate terrains. In this paper, we present our efforts in designing a controller based on capture point control for our thruster-assisted walking model named Harpy and explore its control design possibilities. While capture point control based on centroidal models for bipedal systems has been extensively studied, the incorporation of external forces that can influence the dynamics of linear inverted pendulum models, often used in capture point-based works, has not been explored before. The inclusion of these external forces can lead to interesting interpretations of locomotion, such as virtual buoyancy studied in aquatic-legged locomotion. This paper outlines the dynamical model of our robot, the capture point method we use to assist the upper body stabilization, and the simulation work done to show the controller's feasibility., Comment: Submitted and to be presented at IEEE AIM 2024. arXiv admin note: substantial text overlap with arXiv:2103.15952
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- 2024
22. SWANN: Shuffling Weights in Crossbar Arrays for Enhanced DNN Accuracy in Deeply Scaled Technologies
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Victor, Jeffry, Kim, Dong Eun, Wang, Chunguang, Roy, Kaushik, and Gupta, Sumeet
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Computer Science - Emerging Technologies ,Computer Science - Hardware Architecture - Abstract
Deep neural network (DNN) accelerators employing crossbar arrays capable of in-memory computing (IMC) are highly promising for neural computing platforms. However, in deeply scaled technologies, interconnect resistance severely impairs IMC robustness, leading to a drop in the system accuracy. To address this problem, we propose SWANN - a technique based on shuffling weights in crossbar arrays which alleviates the detrimental effect of wire resistance on IMC. For 8T-SRAM-based 128x128 crossbar arrays in 7nm technology, SWANN enhances the accuracy from 47.78% to 83.5% for ResNet-20/CIFAR-10. We also show that SWANN can be used synergistically with Partial-Word-LineActivation, further boosting the accuracy. Moreover, we evaluate the implications of SWANN for compact ferroelectric-transistorbased crossbar arrays. SWANN incurs minimal hardware overhead, with less than a 1% increase in energy consumption. Additionally, the latency and area overheads of SWANN are ~1% and ~16%, respectively when 1 ADC is utilized per crossbar array.
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- 2024
23. Thruster-Assisted Incline Walking
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Krishnamurthy, Kaushik Venkatesh, Wang, Chenghao, Pitroda, Shreyansh, Salagame, Adarsh, Sihite, Eric, Nemovi, Reza, Ramezani, Alireza, and Gharib, Morteza
- Subjects
Computer Science - Robotics ,Electrical Engineering and Systems Science - Systems and Control - Abstract
In this study, our aim is to evaluate the effectiveness of thruster-assisted steep slope walking for the Husky Carbon, a quadrupedal robot equipped with custom-designed actuators and plural electric ducted fans, through simulation prior to conducting experimental trials. Thruster-assisted steep slope walking draws inspiration from wing-assisted incline running (WAIR) observed in birds, and intriguingly incorporates posture manipulation and thrust vectoring, a locomotion technique not previously explored in the animal kingdom. Our approach involves developing a reduced-order model of the Husky robot, followed by the application of an optimization-based controller utilizing collocation methods and dynamics interpolation to determine control actions. Through simulation testing, we demonstrate the feasibility of hardware implementation of our controller., Comment: 7 pages, 7 figures, submitted to CDC 2024 conference. arXiv admin note: text overlap with arXiv:2405.06070
- Published
- 2024
24. A Super-human Vision-based Reinforcement Learning Agent for Autonomous Racing in Gran Turismo
- Author
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Vasco, Miguel, Seno, Takuma, Kawamoto, Kenta, Subramanian, Kaushik, Wurman, Peter R., and Stone, Peter
- Subjects
Computer Science - Machine Learning ,Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Robotics - Abstract
Racing autonomous cars faster than the best human drivers has been a longstanding grand challenge for the fields of Artificial Intelligence and robotics. Recently, an end-to-end deep reinforcement learning agent met this challenge in a high-fidelity racing simulator, Gran Turismo. However, this agent relied on global features that require instrumentation external to the car. This paper introduces, to the best of our knowledge, the first super-human car racing agent whose sensor input is purely local to the car, namely pixels from an ego-centric camera view and quantities that can be sensed from on-board the car, such as the car's velocity. By leveraging global features only at training time, the learned agent is able to outperform the best human drivers in time trial (one car on the track at a time) races using only local input features. The resulting agent is evaluated in Gran Turismo 7 on multiple tracks and cars. Detailed ablation experiments demonstrate the agent's strong reliance on visual inputs, making it the first vision-based super-human car racing agent., Comment: Accepted at the Reinforcement Learning Conference (RLC) 2024
- Published
- 2024
25. Comparative Analysis of $k$-essence and Quintessence Scalar Field Models: A Data Analysis Approach
- Author
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Hussain, Saddam, Nelleri, Sarath, and Bhattacharya, Kaushik
- Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics ,General Relativity and Quantum Cosmology ,High Energy Physics - Phenomenology ,Physics - Data Analysis, Statistics and Probability - Abstract
We perform a comparative analysis of quintessence and $k$-essence scalar field models in the data analysis perspective. We study the quintessence field with an exponential potential and the $k$-essence field with an inverse square potential in the present work. Before delving into data analysis, we provide a brief perspective on dynamical evolution on both of the models and obtain the stability constraints on the model parameters. We adopt Bayesian inference procedure to estimate the model parameters that best-fit the data. A comprehensive analysis utilizing Observational Hubble data (OHD) and Pantheon+ compilation of Type Ia supernovae (SNIa) shows that $k$-essence model fits the data slightly better than the quintessence model while the evidence of these models in comparison with the $\Lambda$CDM model is weak. The value of the Hubble constant predicted by both the models is in close agreement with the value obtained by the Planck2018 collaboration assuming the $\Lambda$CDM model., Comment: 24 pages, 12 figures, 4 tables
- Published
- 2024
26. GraVITON: Graph based garment warping with attention guided inversion for Virtual-tryon
- Author
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Pathak, Sanhita, Kaushik, Vinay, and Lall, Brejesh
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
Virtual try-on, a rapidly evolving field in computer vision, is transforming e-commerce by improving customer experiences through precise garment warping and seamless integration onto the human body. While existing methods such as TPS and flow address the garment warping but overlook the finer contextual details. In this paper, we introduce a novel graph based warping technique which emphasizes the value of context in garment flow. Our graph based warping module generates warped garment as well as a coarse person image, which is utilised by a simple refinement network to give a coarse virtual tryon image. The proposed work exploits latent diffusion model to generate the final tryon, treating garment transfer as an inpainting task. The diffusion model is conditioned with decoupled cross attention based inversion of visual and textual information. We introduce an occlusion aware warping constraint that generates dense warped garment, without any holes and occlusion. Our method, validated on VITON-HD and Dresscode datasets, showcases substantial state-of-the-art qualitative and quantitative results showing considerable improvement in garment warping, texture preservation, and overall realism., Comment: 18 pages, 7 Figures and 6 Tables
- Published
- 2024
27. Precise asymptotics of reweighted least-squares algorithms for linear diagonal networks
- Author
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Kaushik, Chiraag, Romberg, Justin, and Muthukumar, Vidya
- Subjects
Statistics - Machine Learning ,Computer Science - Machine Learning - Abstract
The classical iteratively reweighted least-squares (IRLS) algorithm aims to recover an unknown signal from linear measurements by performing a sequence of weighted least squares problems, where the weights are recursively updated at each step. Varieties of this algorithm have been shown to achieve favorable empirical performance and theoretical guarantees for sparse recovery and $\ell_p$-norm minimization. Recently, some preliminary connections have also been made between IRLS and certain types of non-convex linear neural network architectures that are observed to exploit low-dimensional structure in high-dimensional linear models. In this work, we provide a unified asymptotic analysis for a family of algorithms that encompasses IRLS, the recently proposed lin-RFM algorithm (which was motivated by feature learning in neural networks), and the alternating minimization algorithm on linear diagonal neural networks. Our analysis operates in a "batched" setting with i.i.d. Gaussian covariates and shows that, with appropriately chosen reweighting policy, the algorithm can achieve favorable performance in only a handful of iterations. We also extend our results to the case of group-sparse recovery and show that leveraging this structure in the reweighting scheme provably improves test error compared to coordinate-wise reweighting., Comment: 25 pages, 3 figures
- Published
- 2024
28. Local structural distortions drive magnetic molecular field in a compositionally complex spinel oxide
- Author
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Nevgi, Rukma, Dey, Subha, Bhattacharya, Nandana, Dan, Tinku, Chakravarty, Sujay, Kaushik, S. D., Klewe, Christoph, Sterbinsky, George E., and Middey, Srimanta
- Subjects
Condensed Matter - Materials Science ,Condensed Matter - Strongly Correlated Electrons - Abstract
A core challenge in understanding high entropy oxides (HEOs) is how these systems, with five or more cations at a crystallographic site, can withstand local distortions while preserving a uniform structure on a larger scale. We address this for spinel HEO by comparatively examining extended X-ray absorption fine structure (EXAFS) on (Mn$_{0.2}$Co$_{0.2}$Ni$_{0.2}$Cu$_{0.2}$Zn$_{0.2}$)Cr$_2$O$_4$ ($A^5$Cr$_2$O$_4$) and its parent counterparts $A$Cr$_2$O$_4$ ($A$= Mn, Co, Ni, Cu, Zn). Unlike the HEO with rock-salt structure, the element-specific distortions in disordered sublattice go beyond the first neighbor here. Moreover, the tetragonal distortion around the Cu$^{2+}$ ion, known as a textbook example of the Jahn-Teller effect, is highly reduced in $A^5$Cr$_2$O$_4$ compared to CuCr$_2$O$_4$. Despite variations in the A-O bond lengths, the inter-cationic distances remained remarkably similar. This affirms a high level of flexibility in the positioning of oxygen, enabling them to adapt to the overall cubic symmetry. Despite containing multiple magnetic ions, the Curie-Weiss temperature and effective magnetic moments of $A^5$Cr$_2$O$_4$ are similar to those of NiCr$_2$O$_4$. This can be attributed to both materials' comparable local bond lengths around Cr, as evidenced by EXAFS analysis. This study conclusively presents a method for elucidating how local structural distortions influence the macroscopic properties of compositionally complex quantum materials.
- Published
- 2024
29. Reassessing constant-roll Warm Inflation
- Author
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Biswas, Sandip, Bhattacharya, Kaushik, and Das, Suratna
- Subjects
Astrophysics - Cosmology and Nongalactic Astrophysics ,General Relativity and Quantum Cosmology ,High Energy Physics - Phenomenology - Abstract
Departing from standard slow-roll conditions is one way of putting the inflationary paradigm to test, and constraining the dynamics of the inflaton field with a constant-rate of roll of the inflaton field, a.k.a. the constant-roll scenario, is one way of exploring such deviation from the standard slow-roll dynamics. In this manuscript we explore such a possibility in a variant inflationary scenario, known as Warm Inflation. We construct and derive the conditions for having constant-roll WI models where inflation lasts at least for 60 $e-$folds, gracefully exits the constant-roll inflation phase, and maintains near thermal equilibrium of the system which is an essential feature of WI in the slow-roll regime. We show that while certain models of WI (the ones with dissipative coefficient as a function of temperature alone) can accommodate constant-roll dynamics, others (with dissipative coefficient as a function of temperature and the inflaton field both) fail to maintain thermal equilibrium once the constant-roll condition is imposed and hence cannot produce a constant-roll WI phase., Comment: Double-column, 14 pages, 6 figures
- Published
- 2024
30. A Comparative Study of CNN, ResNet, and Vision Transformers for Multi-Classification of Chest Diseases
- Author
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Jain, Ananya, Bhardwaj, Aviral, Murali, Kaushik, and Surani, Isha
- Subjects
Electrical Engineering and Systems Science - Image and Video Processing ,Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Machine Learning - Abstract
Large language models, notably utilizing Transformer architectures, have emerged as powerful tools due to their scalability and ability to process large amounts of data. Dosovitskiy et al. expanded this architecture to introduce Vision Transformers (ViT), extending its applicability to image processing tasks. Motivated by this advancement, we fine-tuned two variants of ViT models, one pre-trained on ImageNet and another trained from scratch, using the NIH Chest X-ray dataset containing over 100,000 frontal-view X-ray images. Our study evaluates the performance of these models in the multi-label classification of 14 distinct diseases, while using Convolutional Neural Networks (CNNs) and ResNet architectures as baseline models for comparison. Through rigorous assessment based on accuracy metrics, we identify that the pre-trained ViT model surpasses CNNs and ResNet in this multilabel classification task, highlighting its potential for accurate diagnosis of various lung conditions from chest X-ray images., Comment: 8 pages, 6 figures
- Published
- 2024
31. X-ray and Radio campaign of the Z-source GX 340+0: discovery of X-ray polarization and its implications
- Author
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Bhargava, Yash, Ng, Mason, Zhang, Liang, Balasubramanian, Arvind, Russell, Thomas D., Kaushik, Aman, Jadoliya, Vishal, Ravi, Swati, Bhattacharyya, Sudip, Pahari, Mayukh, Homan, Jeroen, Marshall, Herman L., Chakrabarty, Deepto, and Carotenuto, Francesco
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present the discovery of X-ray polarization from the neutron star low-mass X-ray binary and Z-source, GX~340$+$0, using an Imaging X-ray Polarimetry Explorer (IXPE) observation in March 2024. Along with the IXPE observation, we conducted an extensive X-ray and radio monitoring campaign to ascertain the source properties during and around the IXPE observation. The source was within the horizontal branch throughout the multiwavelength campaign. We measured a significant X-ray polarization in 2--8 keV with polarization degree (PD) = $4.02 \pm 0.35$% and polarization angle (PA) = $37.6 \pm 2.5^\circ$. The energy-dependent polarization indicates that in the 2-2.5 keV energy range, the PA is much lower, $\sim9\pm8^\circ$, while other energy bands are consistent with the PA found over 2.5--8 keV. The simultaneous AstroSat-IXPE spectro-polarimetric observations provide some evidence for independent polarization from various spectral components, hinting at a disparity in the PA from the accretion disk and the Comptonized emission, while suggesting an unpolarized emission from the blackbody component. Radio observations in the 0.7--9 GHz frequency range reveal a non-detection of radio emission in 0.7-1.5 GHz and a significant detection in 5.5--9 GHz, suggesting the presence of a spectral break in 1.5-5.5 GHz. Using ATCA observation we place upper limits on the radio polarization at $<$6% on the linear polarization and $<$4% on the circular polarization at 3$\sigma$ level. We discuss the origin of the X-ray polarization and its implications on the geometry of the spectral components., Comment: Submitted in ApJL, 4 figures, 3 tables
- Published
- 2024
32. Black Hole Search in Dynamic Graphs
- Author
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Kaur, Tanvir, Saxena, Ashish, Mandal, Partha Sarathi, and Mondal, Kaushik
- Subjects
Computer Science - Distributed, Parallel, and Cluster Computing - Abstract
A black hole in a graph is a dangerous site that disposes any incoming agent into that node without leaving any trace of its existence. In the Black Hole Search (BHS) problem, the goal is for at least one agent to survive, locate the position of the black hole, and then terminate. This problem has been extensively studied for static graphs, where the edges do not disappear with time. In dynamic graphs, where the edges may disappear and reappear with time, the problem has only been studied for specific graphs such as rings and cactuses. In this work, we investigate the problem of BHS for general graphs with a much weaker model with respect to the one used for the cases of rings and cactus graphs\cite{bhattacharya_2023, Paola_2024}. We consider two cases: (a) where the adversary can remove at most one edge in each round, and (b) where the adversary can remove at most $f$ edges in each round. In both scenarios, we consider rooted configuration. In the case when the adversary can remove at most one edge from the graph, we provide an algorithm that uses 9 agents to solve the BHS problem in $O(m^2)$ time given that each node $v$ is equipped with $O(\log \delta_v)$ storage in the form of a whiteboard, where $m$ is the number of edges in $G$ and $\delta_v$ is the degree of node $v$. We also prove that it is impossible for $2\delta_{BH}$ many agents with $O(\log n)$ memory to locate the black hole where $\delta_{BH}$ is the degree of the black hole even if the nodes are equipped with whiteboards of $O(\log \delta_v)$ storage. In a scenario where the adversary can remove at most $f$ edges and the initial configuration is rooted, we present an algorithm that uses $6f$ agents to solve the BHS problem. We also prove that solving BHS using $2f+1$ agents starting from a rooted configuration on a general graph is impossible, even with unlimited node storage and infinite agent memory.
- Published
- 2024
33. LLS: Local Learning Rule for Deep Neural Networks Inspired by Neural Activity Synchronization
- Author
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Apolinario, Marco Paul E., Roy, Arani, and Roy, Kaushik
- Subjects
Computer Science - Neural and Evolutionary Computing ,Computer Science - Artificial Intelligence ,Computer Science - Machine Learning - Abstract
Training deep neural networks (DNNs) using traditional backpropagation (BP) presents challenges in terms of computational complexity and energy consumption, particularly for on-device learning where computational resources are limited. Various alternatives to BP, including random feedback alignment, forward-forward, and local classifiers, have been explored to address these challenges. These methods have their advantages, but they can encounter difficulties when dealing with intricate visual tasks or demand considerable computational resources. In this paper, we propose a novel Local Learning rule inspired by neural activity Synchronization phenomena (LLS) observed in the brain. LLS utilizes fixed periodic basis vectors to synchronize neuron activity within each layer, enabling efficient training without the need for additional trainable parameters. We demonstrate the effectiveness of LLS and its variations, LLS-M and LLS-MxM, on multiple image classification datasets, achieving accuracy comparable to BP with reduced computational complexity and minimal additional parameters. Furthermore, the performance of LLS on the Visual Wake Word (VWW) dataset highlights its suitability for on-device learning tasks, making it a promising candidate for edge hardware implementations., Comment: 14 pages, 4 figures
- Published
- 2024
34. Parametrically controlled chiral interface for superconducting quantum devices
- Author
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Cao, Xi, Irfan, Abdullah, Mollenhauer, Michael, Singirikonda, Kaushik, and Pfaff, Wolfgang
- Subjects
Quantum Physics - Abstract
Nonreciprocal microwave routing plays a crucial role for measuring quantum circuits, and allows for realizing cascaded quantum systems for generating and stabilizing entanglement between non-interacting qubits. The most commonly used tools for implementing directionality are ferrite-based circulators. These devices are versatile, but suffer from excess loss, a large footprint, and fixed directionality. For utilizing nonreciprocity in scalable quantum circuits it is desirable to develop efficient integration of low-loss and in-situ controllable directional elements. Here, we report the design and experimental realization of a controllable directional interface that may be integrated directly with superconducting qubits. In the presented device, nonreciprocity is realized through a combination of interference and phase-controlled parametric pumping. We have achieved a maximum directionality of around 30\,dB, and the performance of the device is predicted quantitatively from independent calibration measurements. Using the excellent agreement of model and experiment, we predict that the circuit will be useable as a chiral qubit interface with inefficiencies at the one-percent level or below. Our work provides a route toward isolator-free qubit readout schemes and high-fidelity entanglement generation in all-to-all connected networks of superconducting quantum devices., Comment: 20 pages, 13 figures
- Published
- 2024
35. SADDLe: Sharpness-Aware Decentralized Deep Learning with Heterogeneous Data
- Author
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Choudhary, Sakshi, Aketi, Sai Aparna, and Roy, Kaushik
- Subjects
Computer Science - Machine Learning ,Computer Science - Distributed, Parallel, and Cluster Computing ,Computer Science - Multiagent Systems - Abstract
Decentralized training enables learning with distributed datasets generated at different locations without relying on a central server. In realistic scenarios, the data distribution across these sparsely connected learning agents can be significantly heterogeneous, leading to local model over-fitting and poor global model generalization. Another challenge is the high communication cost of training models in such a peer-to-peer fashion without any central coordination. In this paper, we jointly tackle these two-fold practical challenges by proposing SADDLe, a set of sharpness-aware decentralized deep learning algorithms. SADDLe leverages Sharpness-Aware Minimization (SAM) to seek a flatter loss landscape during training, resulting in better model generalization as well as enhanced robustness to communication compression. We present two versions of our approach and conduct extensive experiments to show that SADDLe leads to 1-20% improvement in test accuracy compared to other existing techniques. Additionally, our proposed approach is robust to communication compression, with an average drop of only 1% in the presence of up to 4x compression.
- Published
- 2024
36. Stereo-Knowledge Distillation from dpMV to Dual Pixels for Light Field Video Reconstruction
- Author
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Garg, Aryan, Mallampali, Raghav, Joshi, Akshat, Govindarajan, Shrisudhan, and Mitra, Kaushik
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
Dual pixels contain disparity cues arising from the defocus blur. This disparity information is useful for many vision tasks ranging from autonomous driving to 3D creative realism. However, directly estimating disparity from dual pixels is less accurate. This work hypothesizes that distilling high-precision dark stereo knowledge, implicitly or explicitly, to efficient dual-pixel student networks enables faithful reconstructions. This dark knowledge distillation should also alleviate stereo-synchronization setup and calibration costs while dramatically increasing parameter and inference time efficiency. We collect the first and largest 3-view dual-pixel video dataset, dpMV, to validate our explicit dark knowledge distillation hypothesis. We show that these methods outperform purely monocular solutions, especially in challenging foreground-background separation regions using faithful guidance from dual pixels. Finally, we demonstrate an unconventional use case unlocked by dpMV and implicit dark knowledge distillation from an ensemble of teachers for Light Field (LF) video reconstruction. Our LF video reconstruction method is the fastest and most temporally consistent to date. It remains competitive in reconstruction fidelity while offering many other essential properties like high parameter efficiency, implicit disocclusion handling, zero-shot cross-dataset transfer, geometrically consistent inference on higher spatial-angular resolutions, and adaptive baseline control. All source code is available at the anonymous repository https://github.com/Aryan-Garg., Comment: International Conference of Computational Photography (ICCP 2024), 11 pages and 12 figures
- Published
- 2024
37. Adhesion of a nematic elastomer cylinder
- Author
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Maghsoodi, Ameneh and Bhattacharya, Kaushik
- Subjects
Condensed Matter - Soft Condensed Matter - Abstract
Liquid crystal elastomers are cross-linked elastomer networks with liquid crystal mesogens incorporated into the main or side chain. Polydomain liquid crystalline (nematic) elastomers exhibit unusual mechanical properties like soft elasticity, where the material deforms at nearly constant stress, due to the reorientation of mesogens. In this paper, we use numerical simulation to study the implication of the remarkable elastic softness on a classical problem of adhesion. This study reveals that the soft elasticity of nematic elastomers dramatically affects the interfacial stress distribution at the interface of a nematic elastomer cylinder adhered to a rigid substrate. The stress near the edge of the nematic cylinder under tensile load deviates from the singular behavior predicted for linear elastic materials, and the maximum normal stress reduces dramatically. Moreover, the location of maximum interfacial stress shifts from the edge to the center of the nematic cylinder when the applied tensile force goes beyond a critical value. We discuss the implications for adhesion. The results are consistent with the available experimental data.
- Published
- 2024
38. Early phase simultaneous multi-band observations of Type II supernova SN 2024ggi with Mephisto
- Author
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Chen, Xinlei, Kumar, Brajesh, Er, Xinzhong, Guo, Helong, Yang, Yuan-Pei, Lin, Weikang, Fang, Yuan, Du, Guowang, Liu, Chenxu, Zhao, Jiewei, Zhang, Tianyu, Bao, Yuxi, Zou, Xingzhu, Pan, Yu, Wang, Yu, Zhu, Xufeng, Chatterjee, Kaushik, Liu, Xiangkun, Liu, Dezi, Lagioia, Edoardo P., Rangwal, Geeta, Zhong, Shiyan, Zhang, Jinghua, Lian, Jianhui, Cai, Yongzhi, Zhang, Yangwei, and Liu, Xiaowei
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present early-phase good cadence simultaneous multi-band ($ugi$, $vrz$--bands) imaging of nearby supernova SN 2024ggi, which exploded in the nearby galaxy, NGC~3621. A quick follow-up was conducted within less than a day after the explosion and continued $\sim$23 days. The $uvg$-band light curves display a rapid rise ($\sim$1.4 mag day$^{-1}$) to maximum in $\sim$4 days and absolute magnitude $M_{g}\sim$--17.75 mag. The post-peak decay rate in redder bands is $\sim$0.01 mag day$^{-1}$. Different colors (e.g., $u-g$ and $v-r$) of SN~2024ggi are slightly redder than SN~2023ixf. A significant rise ($\sim$12.5 kK) in black-body temperature (optical) was noticed within $\sim$2 days after the explosion, which successively decreased, indicating shock break out inside a dense circumstellar medium (CSM) surrounding the progenitor. Using semi-analytical modeling, the ejecta mass and progenitor radius were estimated as 1.2 M$_{\odot}$ and $\sim$550 R$_{\odot}$, respectively. The archival deep images ($g,r,i,z$-bands) from the Dark Energy Camera Legacy Survey (DECaLS) were examined, and a possible progenitor was detected in each band ($\sim$22--22.5 mag) and had a mass range of 14--17 M$_{\odot}$., Comment: Pages 9, Table 1, Figures 7
- Published
- 2024
39. Towards Adaptive IMFs -- Generalization of utility functions in Multi-Agent Frameworks
- Author
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Dey, Kaushik, Perepu, Satheesh K., Das, Abir, and Dasgupta, Pallab
- Subjects
Computer Science - Machine Learning ,Computer Science - Artificial Intelligence - Abstract
Intent Management Function (IMF) is an integral part of future-generation networks. In recent years, there has been some work on AI-based IMFs that can handle conflicting intents and prioritize the global objective based on apriori definition of the utility function and accorded priorities for competing intents. Some of the earlier works use Multi-Agent Reinforcement Learning (MARL) techniques with AdHoc Teaming (AHT) approaches for efficient conflict handling in IMF. However, the success of such frameworks in real-life scenarios requires them to be flexible to business situations. The intent priorities can change and the utility function, which measures the extent of intent fulfilment, may also vary in definition. This paper proposes a novel mechanism whereby the IMF can generalize to different forms of utility functions and change of intent priorities at run-time without additional training. Such generalization ability, without additional training requirements, would help to deploy IMF in live networks where customer intents and priorities change frequently. Results on the network emulator demonstrate the efficacy of the approach, scalability for new intents, outperforming existing techniques that require additional training to achieve the same degree of flexibility thereby saving cost, and increasing efficiency and adaptability., Comment: Accepted in Netsoft-2024 conference
- Published
- 2024
40. Multiplicity of solutions for mixed local-nonlocal elliptic equations with singular nonlinearity
- Author
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Bal, Kaushik and Das, Stuti
- Subjects
Mathematics - Analysis of PDEs - Abstract
We will prove multiplicity results for the mixed local-nonlocal elliptic equation of the form \begin{eqnarray} \begin{split} -\Delta_pu+(-\Delta)_p^s u&=\frac{\lambda}{u^{\gamma}}+u^r \text { in } \Omega, \\u&>0 \text{ in } \Omega,\\u&=0 \text { in }\mathbb{R}^n \backslash \Omega; \end{split} \end{eqnarray} where \begin{equation*} (-\Delta )_p^s u(x)= c_{n,s}\operatorname{P.V.}\int_{\mathbb{R}^n}\frac{|u(x)-u(y)|^{p-2}(u(x)-u(y))}{|x-y|^{n+sp}} d y, \end{equation*} and $-\Delta_p$ is the usual $p$-Laplace operator. Under the assumptions that $\Omega$ is a bounded domain in $\mathbb{R}^{n}$ with regular enough boundary, $p>1$, $n> p$, $s\in(0,1)$, $\lambda>0$ and $r\in(p-1,p^*-1)$ where $p^*$ is the critical Sobolev exponent, we will show there exist at least two weak solutions to our problem for $0<\gamma<1$ and some certain values of $\lambda$. Further, for every $\gamma>0$, assuming strict convexity of $\Omega$, for $p=2$ and $s\in(0,1/2)$, we will show the existence of at least two positive weak solutions to the problem, for small values of $\lambda$, extending the result of \cite{garaingeometric}. Here $c_{n,s}$ is a suitable normalization constant, and $\operatorname{P.V.}$ stands for Cauchy Principal Value., Comment: A few typos were corrected
- Published
- 2024
41. Narrow-Path, Dynamic Walking Using Integrated Posture Manipulation and Thrust Vectoring
- Author
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Krishnamurthy, Kaushik Venkatesh, Wang, Chenghao, Pitroda, Shreyansh, Salagame, Adarsh, Sihite, Eric, Nemovi, Reza, Ramezani, Alireza, and Gharib, Morteza
- Subjects
Computer Science - Robotics ,Electrical Engineering and Systems Science - Systems and Control - Abstract
This research concentrates on enhancing the navigational capabilities of Northeastern Universitys Husky, a multi-modal quadrupedal robot, that can integrate posture manipulation and thrust vectoring, to traverse through narrow pathways such as walking over pipes and slacklining. The Husky is outfitted with thrusters designed to stabilize its body during dynamic walking over these narrow paths. The project involves modeling the robot using the HROM (Husky Reduced Order Model) and developing an optimal control framework. This framework is based on polynomial approximation of the HROM and a collocation approach to derive optimal thruster commands necessary for achieving dynamic walking on narrow paths. The effectiveness of the modeling and control design approach is validated through simulations conducted using Matlab., Comment: arXiv admin note: text overlap with arXiv:2312.12586
- Published
- 2024
42. QR factorization of ill-conditioned tall-and-skinny matrices on distributed-memory systems
- Author
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Mijić, Nenad, Kaushik, Abhiram, and Davidović, Davor
- Subjects
Computer Science - Distributed, Parallel, and Cluster Computing ,Computer Science - Data Structures and Algorithms ,Computer Science - Performance - Abstract
In this paper we present a novel algorithm developed for computing the QR factorisation of extremely ill-conditioned tall-and-skinny matrices on distributed memory systems. The algorithm is based on the communication-avoiding CholeskyQR2 algorithm and its block Gram-Schmidt variant. The latter improves the numerical stability of the CholeskyQR2 algorithm and significantly reduces the loss of orthogonality even for matrices with condition numbers up to $10^{15}$. Currently, there is no distributed GPU version of this algorithm available in the literature which prevents the application of this method to very large matrices. In our work we provide a distributed implementation of this algorithm and also introduce a modified version that improves the performance, especially in the case of extremely ill-conditioned matrices. The main innovation of our approach lies in the interleaving of the CholeskyQR steps with the Gram-Schmidt orthogonalisation, which ensures that update steps are performed with fully orthogonalised panels. The obtained orthogonality and numerical stability of our modified algorithm is equivalent to CholeskyQR2 with Gram-Schmidt and other state-of-the-art methods. Weak scaling tests performed with our test matrices show significant performance improvements. In particular, our algorithm outperforms state-of-the-art Householder-based QR factorisation algorithms available in ScaLAPACK by a factor of $6$ on CPU-only systems and up to $80\times$ on GPU-based systems with distributed memory., Comment: 12 pages, 10 figures, 2 tables
- Published
- 2024
43. An Overview of Intelligent Meta-surfaces for 6G and Beyond: Opportunities, Trends, and Challenges
- Author
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Katwe, Mayur, Kaushik, Aryan, Mohjazi, Lina, Abualhayja'a, Mohammad, Dardari, Davide, Singh, Keshav, Imran, Muhammad Ali, Butt, M. Majid, and Dobre, Octavia A.
- Subjects
Computer Science - Networking and Internet Architecture ,Electrical Engineering and Systems Science - Signal Processing - Abstract
With the impending arrival of the sixth generation (6G) of wireless communication technology, the telecommunications landscape is poised for another revolutionary transformation. At the forefront of this evolution are intelligent meta-surfaces (IS), emerging as a disruptive physical layer technology with the potential to redefine the capabilities and performance metrics of future wireless networks. As 6G evolves from concept to reality, industry stakeholders, standards organizations, and regulatory bodies are collaborating to define the specifications, protocols, and interoperability standards governing IS deployment. Against this background, this article delves into the ongoing standardization efforts, emerging trends, potential opportunities, and prevailing challenges surrounding the integration of IS into the framework of 6G and beyond networks. Specifically, it provides a tutorial-style overview of recent advancements in IS and explores their potential applications within future networks beyond 6G. Additionally, the article identifies key challenges in the design and implementation of various types of intelligent surfaces, along with considerations for their practical standardization. Finally, it highlights potential future prospects in this evolving field.
- Published
- 2024
44. Confidential and Protected Disease Classifier using Fully Homomorphic Encryption
- Author
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Malik, Aditya, Ratha, Nalini, Yalavarthi, Bharat, Sharma, Tilak, Kaushik, Arjun, and Jutla, Charanjit
- Subjects
Computer Science - Cryptography and Security ,Computer Science - Machine Learning - Abstract
With the rapid surge in the prevalence of Large Language Models (LLMs), individuals are increasingly turning to conversational AI for initial insights across various domains, including health-related inquiries such as disease diagnosis. Many users seek potential causes on platforms like ChatGPT or Bard before consulting a medical professional for their ailment. These platforms offer valuable benefits by streamlining the diagnosis process, alleviating the significant workload of healthcare practitioners, and saving users both time and money by avoiding unnecessary doctor visits. However, Despite the convenience of such platforms, sharing personal medical data online poses risks, including the presence of malicious platforms or potential eavesdropping by attackers. To address privacy concerns, we propose a novel framework combining FHE and Deep Learning for a secure and private diagnosis system. Operating on a question-and-answer-based model akin to an interaction with a medical practitioner, this end-to-end secure system employs Fully Homomorphic Encryption (FHE) to handle encrypted input data. Given FHE's computational constraints, we adapt deep neural networks and activation functions to the encryted domain. Further, we also propose a faster algorithm to compute summation of ciphertext elements. Through rigorous experiments, we demonstrate the efficacy of our approach. The proposed framework achieves strict security and privacy with minimal loss in performance.
- Published
- 2024
45. ViTALS: Vision Transformer for Action Localization in Surgical Nephrectomy
- Author
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Chandra, Soumyadeep, Chowdhury, Sayeed Shafayet, Yong, Courtney, Sundaram, Chandru P., and Roy, Kaushik
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
Surgical action localization is a challenging computer vision problem. While it has promising applications including automated training of surgery procedures, surgical workflow optimization, etc., appropriate model design is pivotal to accomplishing this task. Moreover, the lack of suitable medical datasets adds an additional layer of complexity. To that effect, we introduce a new complex dataset of nephrectomy surgeries called UroSlice. To perform the action localization from these videos, we propose a novel model termed as `ViTALS' (Vision Transformer for Action Localization in Surgical Nephrectomy). Our model incorporates hierarchical dilated temporal convolution layers and inter-layer residual connections to capture the temporal correlations at finer as well as coarser granularities. The proposed approach achieves state-of-the-art performance on Cholec80 and UroSlice datasets (89.8% and 66.1% accuracy, respectively), validating its effectiveness., Comment: Nephrectomy surgery, Surgical Phase Recognition, Surgical Workflow Segmentation, 11 pages, 2 figures, 2 tables
- Published
- 2024
46. Converting Anyone's Voice: End-to-End Expressive Voice Conversion with a Conditional Diffusion Model
- Author
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Du, Zongyang, Lu, Junchen, Zhou, Kun, Kaushik, Lakshmish, and Sisman, Berrak
- Subjects
Electrical Engineering and Systems Science - Audio and Speech Processing ,Computer Science - Sound - Abstract
Expressive voice conversion (VC) conducts speaker identity conversion for emotional speakers by jointly converting speaker identity and emotional style. Emotional style modeling for arbitrary speakers in expressive VC has not been extensively explored. Previous approaches have relied on vocoders for speech reconstruction, which makes speech quality heavily dependent on the performance of vocoders. A major challenge of expressive VC lies in emotion prosody modeling. To address these challenges, this paper proposes a fully end-to-end expressive VC framework based on a conditional denoising diffusion probabilistic model (DDPM). We utilize speech units derived from self-supervised speech models as content conditioning, along with deep features extracted from speech emotion recognition and speaker verification systems to model emotional style and speaker identity. Objective and subjective evaluations show the effectiveness of our framework. Codes and samples are publicly available., Comment: Accepted by Speaker Odyssey 2024
- Published
- 2024
47. Insight-HXMT View of the BHC Swift J1727.8-1613 during its outburst in 2023
- Author
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Chatterjee, Kaushik, Mondal, Santanu, Singh, Chandra B., and Sugizaki, Mutsumi
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
The transient Galactic black hole candidate Swift\,J1727.8-1613 went through an outburst for the very first time that started in August 2023 and lasted for almost 6 months. We study the timing and spectral properties of this source using publicly available archival {\it Insight-HXMT} data for the first 10 observation IDs that last from MJD 60181 to 60198 with a total of 92 exposures for all three energy bands. We extracted the quasi-periodic oscillation properties by model fitting the power density spectrum and from those properties we designate that the QPOs are type-C in nature. We also conclude that the origin of the QPOs could be the shock instabilities in the transonic advective accretion flows around black holes. The spectral analysis was performed using simultaneous data from the three on-board instruments LE, ME, and HE of \textit{Insight-HXMT} in the broad energy band of $2-150 $ keV. To achieve the best fit, spectral fitting required a combination of models e.g. interstellar absorption, power-law, multi-color disk-blackbody continuum, gaussian emission/absorption, and reflection by neutral material. From the spectral properties, we found that the source was in an intermediate state at the start of the analysis period and was making a transition toward the softer states. The inner edge of the accretion disk moved inward in progressive days following the spectral nature. We found that the source has a high inclination. The average hydrogen column density estimated from the model fitting is $0.27_{-0.17}^{+0.08}\times10^{22}$ cm$^{-2}$., Comment: Submitted to AAS (19 pages, 8 figures, 4 tables)
- Published
- 2024
48. Testing uniformity on the circle using spacings when data are rounded
- Author
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Jammalamadaka, S Rao, Ghosh, Kaushik, and Akiri, Sridhar
- Subjects
Mathematical Sciences ,Statistics ,Circular data ,Spacings ,Rounding ,Test for uniformity ,Rao's spacing test ,Applied Mathematics ,Econometrics ,Statistics & Probability - Published
- 2024
49. MIPI 2024 Challenge on Nighttime Flare Removal: Methods and Results
- Author
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Dai, Yuekun, Zhang, Dafeng, Li, Xiaoming, Yue, Zongsheng, Li, Chongyi, Zhou, Shangchen, Feng, Ruicheng, Yang, Peiqing, Jin, Zhezhu, Liu, Guanqun, Loy, Chen Change, Zhang, Lize, Liu, Shuai, Feng, Chaoyu, Wang, Luyang, Chen, Shuan, Shao, Guangqi, Wang, Xiaotao, Lei, Lei, Yang, Qirui, Cheng, Qihua, Xu, Zhiqiang, Liu, Yihao, Yue, Huanjing, Yang, Jingyu, Vasluianu, Florin-Alexandru, Wu, Zongwei, Ciubotariu, George, Timofte, Radu, Zhang, Zhao, Zhao, Suiyi, Wang, Bo, Zuo, Zhichao, Wei, Yanyan, Teja, Kuppa Sai Sri, A, Jayakar Reddy, Rongali, Girish, Mitra, Kaushik, Ma, Zhihao, Liu, Yongxu, Zhang, Wanying, Shang, Wei, He, Yuhong, Peng, Long, Yu, Zhongxin, Luo, Shaofei, Wang, Jian, Miao, Yuqi, Li, Baiang, Wei, Gang, Verma, Rakshank, Maheshwari, Ritik, Tekchandani, Rahul, Hambarde, Praful, Tazi, Satya Narayan, Vipparthi, Santosh Kumar, Murala, Subrahmanyam, Zhang, Haopeng, Hou, Yingli, Yao, Mingde, S, Levin M, Sundararajan, Aniruth, and A, Hari Kumar
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
The increasing demand for computational photography and imaging on mobile platforms has led to the widespread development and integration of advanced image sensors with novel algorithms in camera systems. However, the scarcity of high-quality data for research and the rare opportunity for in-depth exchange of views from industry and academia constrain the development of mobile intelligent photography and imaging (MIPI). Building on the achievements of the previous MIPI Workshops held at ECCV 2022 and CVPR 2023, we introduce our third MIPI challenge including three tracks focusing on novel image sensors and imaging algorithms. In this paper, we summarize and review the Nighttime Flare Removal track on MIPI 2024. In total, 170 participants were successfully registered, and 14 teams submitted results in the final testing phase. The developed solutions in this challenge achieved state-of-the-art performance on Nighttime Flare Removal. More details of this challenge and the link to the dataset can be found at https://mipi-challenge.org/MIPI2024/., Comment: CVPR 2024 Mobile Intelligent Photography and Imaging (MIPI) Workshop--Nighttime Flare Removal Challenge Report. Website: https://mipi-challenge.org/MIPI2024/
- Published
- 2024
50. Calculating the Capacity Region of a Quantum Switch
- Author
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Tillman, Ian, Vasantam, Thirupathaiah, Towsley, Don, and Seshadreesan, Kaushik P.
- Subjects
Quantum Physics - Abstract
Quantum repeaters are necessary to fully realize the capabilities of the emerging quantum internet, especially applications involving distributing entanglement across long distances. A more general notion of this can be called a quantum switch, which connects to many users and can act as a repeater to create end-to-end entanglement between different subsets of these users. Here we present a method of calculating the capacity region of both discrete- and continuous-variable quantum switches that in general support mixed-partite entanglement generation. The method uses tools from convex analysis to generate the boundaries of the capacity region. We show example calculations with illustrative topologies and perform simulations to support the analytical results., Comment: 11 pages, 7 figures. Submitting to IEEE International Conference on Quantum Computing and Engineering (QCE), 2024
- Published
- 2024
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