155,293 results on '"Gautam, A."'
Search Results
2. Structural Modification and CD8+ Cells Distribution of Uterus in Pregnancy of Ewes
- Author
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Islam, M.M., Das, P., Malakar, R., and Gautam, A.K.
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- 2023
- Full Text
- View/download PDF
3. Diagnosing electronic phases of matter using photonic correlation functions
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Nambiar, Gautam, Grankin, Andrey, and Hafezi, Mohammad
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Condensed Matter - Strongly Correlated Electrons ,Quantum Physics - Abstract
In the past couple of decades, there have been significant advances in measuring quantum properties of light, such as quadratures of squeezed light and single-photon counting. Here, we explore whether such tools can be leveraged to probe electronic correlations in the many-body quantum regime. Specifically, we show that it is possible to probe certain spin, charge, and topological orders in an electronic system by measuring the quadrature and correlation functions of photons scattered off it. We construct a mapping from the correlation functions of the scattered photons to those of a correlated insulator, particularly for Mott insulators described by a single-band Hubbard model at half-filling. We show how frequency filtering before photodetection plays a crucial role in determining this mapping. If the ground state of the insulator is a gapped spin liquid, we show that a $G^{(2)}$ (two-photon coherence) measurement can detect the presence of anyonic excitations with fractional mutual statistics. We also show that homodyne measurements can be used to detect expectation values of static spin chirality operators on both the kagome and triangular lattices, thus being useful in detecting chiral spin liquids. Moreover, a slew of hitherto unmeasured spin-spin and spin-charge correlation functions of the material can be extracted from photonic correlations. This work opens up access to probe correlated materials, beyond the linear response paradigm, by detecting quantum properties of scattered light.
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- 2024
4. Communication-Efficient Federated Learning over Wireless Channels via Gradient Sketching
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Gattani, Vineet Sunil, Zhang, Junshan, and Dasarathy, Gautam
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Computer Science - Machine Learning - Abstract
Large-scale federated learning (FL) over wireless multiple access channels (MACs) has emerged as a crucial learning paradigm with a wide range of applications. However, its widespread adoption is hindered by several major challenges, including limited bandwidth shared by many edge devices, noisy and erroneous wireless communications, and heterogeneous datasets with different distributions across edge devices. To overcome these fundamental challenges, we propose Federated Proximal Sketching (FPS), tailored towards band-limited wireless channels and handling data heterogeneity across edge devices. FPS uses a count sketch data structure to address the bandwidth bottleneck and enable efficient compression while maintaining accurate estimation of significant coordinates. Additionally, we modify the loss function in FPS such that it is equipped to deal with varying degrees of data heterogeneity. We establish the convergence of the FPS algorithm under mild technical conditions and characterize how the bias induced due to factors like data heterogeneity and noisy wireless channels play a role in the overall result. We complement the proposed theoretical framework with numerical experiments that demonstrate the stability, accuracy, and efficiency of FPS in comparison to state-of-the-art methods on both synthetic and real-world datasets. Overall, our results show that FPS is a promising solution to tackling the above challenges of FL over wireless MACs.
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- 2024
5. Community search signatures as foundation features for human-centered geospatial modeling
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Sun, Mimi, Kamath, Chaitanya, Agarwal, Mohit, Muslim, Arbaaz, Yee, Hector, Schottlander, David, Bavadekar, Shailesh, Efron, Niv, Shetty, Shravya, and Prasad, Gautam
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Computer Science - Machine Learning - Abstract
Aggregated relative search frequencies offer a unique composite signal reflecting people's habits, concerns, interests, intents, and general information needs, which are not found in other readily available datasets. Temporal search trends have been successfully used in time series modeling across a variety of domains such as infectious diseases, unemployment rates, and retail sales. However, most existing applications require curating specialized datasets of individual keywords, queries, or query clusters, and the search data need to be temporally aligned with the outcome variable of interest. We propose a novel approach for generating an aggregated and anonymized representation of search interest as foundation features at the community level for geospatial modeling. We benchmark these features using spatial datasets across multiple domains. In zip codes with a population greater than 3000 that cover over 95% of the contiguous US population, our models for predicting missing values in a 20% set of holdout counties achieve an average $R^2$ score of 0.74 across 21 health variables, and 0.80 across 6 demographic and environmental variables. Our results demonstrate that these search features can be used for spatial predictions without strict temporal alignment, and that the resulting models outperform spatial interpolation and state of the art methods using satellite imagery features., Comment: 8 pages, 8 figures, presented at the DMLR workshop at ICML 2024
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- 2024
6. Collective excitations and universal coarsening dynamics of a spin-orbit-coupled spin-1 Bose-Einstein condensate
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Rajat, Banger, Paramjeet, and Gautam, Sandeep
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Condensed Matter - Quantum Gases - Abstract
We study the collective excitation spectrum of a Raman-induced spin-orbit-coupled spin-1 Bose-Einstein condensate confined in a quasi-one-dimensional harmonic trap while varying either the Raman coupling or quadratic Zeeman term by using the Bogoliubov approach. A few low-lying modes, which can be used to delineate the phase boundaries, are identified by exciting them with suitable perturbations. We also investigate the coarsening dynamics of a homogeneous quasi-two-dimensional spin-orbit-coupled spin-1 condensate by quenching from the zero-momentum into the plane wave phase through a sudden change in Raman coupling strength. We demonstrate that the correlation function of the order parameter displays dynamic scaling during the late-time dynamics, allowing us to determine the dynamic critical exponent.
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- 2024
7. Behavior of water and aqueous LiCl solutions confined in cylindrical silica pores: A wide temperature range molecular dynamics simulation study
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Gautam, Siddharth, Vlcek, Lukas, Mamontov, Eugene, and Cole, David
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Condensed Matter - Soft Condensed Matter ,Physics - Chemical Physics - Abstract
We report here a molecular dynamics simulation study on water and aqueous LiCl solutions confined in 1.6 nm cylindrical pores of silica to investigate a dynamical cross-over, observed earlier experimentally, wherein LiCl slows down confined water at high temperatures but makes it faster at lower temperatures. The cross-over observed in the experiments is reproduced in the simulations, albeit at lower temperature. Moreover, the cross-over encompasses all aspects of dynamics including translation as well as rotation. Both addition of LiCl and confinement result in a breaking of hydrogen bond network in confined water, eliminating the need for long jumps via exchange of hydrogen bonded partner molecules. This lowers the activation energy for diffusion in the electrolyte solution compared to pure confined water and leads to the dynamical cross-over seen at lower temperatures. Our results thus provide an explanation to the experimentally observed phenomena and provide important insights on the interplay of confinement, temperature and presence of electrolytes on the dynamical behavior of nano-confined water., Comment: 13 pages with 8 figures in the main article along with a supplement appended at the end with 2 tables and 1 figure
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- 2024
8. The Interplay Between Physical Activity, Protein Consumption, and Sleep Quality in Muscle Protein Synthesis
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Devkota, Ayush, Gautam, Manakamana, Dhakal, Uttam, Devkota, Suman, Gupta, Gaurav Kumar, Nepal, Ujjwal, Dhuru, Amey Dinesh, and Singh, Aniket Kumar
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Quantitative Biology - Tissues and Organs ,Quantitative Biology - Cell Behavior - Abstract
This systematic review examines the synergistic and individual influences of resistance exercise, dietary protein supplementation, and sleep/recovery on muscle protein synthesis (MPS). Electronic databases such as Scopus, Google Scholar, and Web of Science were extensively used. Studies were selected based on relevance to the criteria and were ensured to be directly applicable to the objectives. Research indicates that a protein dose of 20 to 25 grams maximally stimulates MPS post-resistance training. It is observed that physically frail individuals aged 76 to 92 and middle-aged adults aged 62 to 74 have lower mixed muscle protein synthetic rates than individuals aged 20 to 32. High-whey protein and leucine-enriched supplements enhance MPS more efficiently than standard dairy products in older adults engaged in resistance programs. Similarly, protein intake before sleep boosts overnight MPS rates, which helps prevent muscle loss associated with sleep debt, exercise-induced damage, and muscle-wasting conditions like sarcopenia and cachexia. Resistance exercise is a functional intervention to achieve muscular adaptation and improve function. Future research should focus on variables such as fluctuating fitness levels, age groups, genetics, and lifestyle factors to generate more accurate and beneficial results.
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- 2024
9. Latent Weight Diffusion: Generating Policies from Trajectories
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Hegde, Shashank, Salhotra, Gautam, and Sukhatme, Gaurav S.
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Computer Science - Machine Learning ,Computer Science - Artificial Intelligence ,Computer Science - Robotics - Abstract
With the increasing availability of open-source robotic data, imitation learning has emerged as a viable approach for both robot manipulation and locomotion. Currently, large generalized policies are trained to predict controls or trajectories using diffusion models, which have the desirable property of learning multimodal action distributions. However, generalizability comes with a cost - namely, larger model size and slower inference. Further, there is a known trade-off between performance and action horizon for Diffusion Policy (i.e., diffusing trajectories): fewer diffusion queries accumulate greater trajectory tracking errors. Thus, it is common practice to run these models at high inference frequency, subject to robot computational constraints. To address these limitations, we propose Latent Weight Diffusion (LWD), a method that uses diffusion to learn a distribution over policies for robotic tasks, rather than over trajectories. Our approach encodes demonstration trajectories into a latent space and then decodes them into policies using a hypernetwork. We employ a diffusion denoising model within this latent space to learn its distribution. We demonstrate that LWD can reconstruct the behaviors of the original policies that generated the trajectory dataset. LWD offers the benefits of considerably smaller policy networks during inference and requires fewer diffusion model queries. When tested on the Metaworld MT10 benchmark, LWD achieves a higher success rate compared to a vanilla multi-task policy, while using models up to ~18x smaller during inference. Additionally, since LWD generates closed-loop policies, we show that it outperforms Diffusion Policy in long action horizon settings, with reduced diffusion queries during rollout.
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- 2024
10. The EMC Effect of Tritium and Helium-3 from the JLab MARATHON Experiment
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Abrams, D., Albataineh, H., Aljawrneh, B. S., Alsalmi, S., Androic, D., Aniol, K., Armstrong, W., Arrington, J., Atac, H., Averett, T., Gayoso, C. Ayerbe, Bai, X., Bane, J., Barcus, S., Beck, A., Bellini, V., Bhatt, H., Bhetuwal, D., Biswas, D., Blyth, D., Boeglin, W., Bulumulla, D., Butler, J., Camsonne, A., Carmignotto, M., Castellanos, J., Chen, J. -P., Cloët, I. C., Cohen, E. O., Covrig, S., Craycraft, K., Cruz-Torres, R., Dongwi, B., Duran, B., Dutta, D., Fomin, N., Fuchey, E., Gal, C., Gautam, T. N., Gilad, S., Gnanvo, K., Gogami, T., Gomez, J., Gu, C., Habarakada, A., Hague, T., Hansen, J. -O., Hattawy, M., Hauenstein, F., Higinbotham, D. W., Holt, R. J., Hughes, E. W., Hyde, C., Ibrahim, H., Jian, S., Joosten, S., Karki, A., Karki, B., Katramatou, A. T., Keith, C., Keppel, C., Khachatryan, M., Khachatryan, V., Khanal, A., Kievsky, A., King, D., King, P. M., Korover, I., Kulagin, S. A., Kumar, K. S., Kutz, T., Lashley-Colthirst, N., Li, S., Li, W., Liu, H., Liuti, S., Liyanage, N., Markowitz, P., McClellan, R. E., Meekins, D., Beck, S. Mey-Tal, Meziani, Z. -E., Michaels, R., Mihovilovic, M., Nelyubin, V., Nguyen, D., Nuruzzaman, Nycz, M., Obrecht, R., Olson, M., Owen, V. F., Pace, E., Pandey, B., Pandey, V., Paolone, M., Papadopoulou, A., Park, S., Paul, S., Petratos, G. G., Petti, R., Piasetzky, E., Pomatsalyuk, R., Premathilake, S., Puckett, A. J. R., Punjabi, V., Ransome, R. D., Rashad, M. N. H., Reimer, P. E., Riordan, S., Roche, J., Salmè, G., Santiesteban, N., Sawatzky, B., Scopetta, S., Schmidt, A., Schmookler, B., Segal, J., Segarra, E. P., Shahinyan, A., Širca, S., Sparveris, N., Su, T., Suleiman, R., Szumila-Vance, H., Tadepalli, A. S., Tang, L., Tireman, W., Tortorici, F., Urciuoli, G. M., Wojtsekhowski, B., Wood, S., Ye, Z. H., Ye, Z. Y., and Zhang, J.
- Subjects
Nuclear Experiment - Abstract
Measurements of the EMC effect in the tritium and helium-3 mirror nuclei are reported. The data were obtained by the MARATHON Jefferson Lab experiment, which performed deep inelastic electron scattering from deuterium and the three-body nuclei, using a cryogenic gas target system and the High Resolution Spectrometers of the Hall A Facility of the Lab. The data cover the Bjorken $x$ range from 0.20 to 0.83, corresponding to a squared four-momentum transfer $Q^2$ range from 2.7 to $11.9\gevsq$, and to an invariant mass $W$ of the final hadronic state greater than 1.84 GeV/${\it c}^2$. The tritium EMC effect measurement is the first of its kind. The MARATHON experimental results are compared to results from previous measurements by DESY-HERMES and JLab-Hall C experiments, as well as with few-body theoretical predictions., Comment: arXiv admin note: text overlap with arXiv:2104.05850
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- 2024
11. Supersymmetry-Driven Quantum Gate Design Based on Feynman Path Integral and TPCP Map Optimization
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Parthasarathy, Harish, Aggarwal, Monika, and Gautam, Kumar
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Quantum Physics ,Physics - Computational Physics - Abstract
We use supersymmetry to enlarge the dimension of the Hilbert space on which the unitary evolution of the state of the quantum fields acts. We discuss how to control the unitary evolution or TPCP maps generated by the quantum evolution of the fields by controlling the vacuum expectations of other fields in the theory. This amounts to breaking supersymmetry using control vacuum expectation values of the other fields. The evolution of the wave functional or TPCP maps obtained by tracing out over other fields is based on the Feynman path integral formula for the fields. By using the methods of quantum stochastic filtering, we estimate the evolving state of the fields from non-demolition noise measurements and then design a family of TPCP maps evolving in time whose outputs match the estimated evolving state. In this way, we are able to simulate the evolution of the state of the quantum noisy fields. Direct matching of the designed TPCP map to output the evolving system state is not possible since there is no way by which we can determine the exact evolving state, we can only estimate it using non-demolition measurements. The family of designed TPCP maps can be based on using a simulated master equation with unknown parameters incorporated into the Hamiltonian and the other Lindblad operators, chosen so as to match the state outputted by the quantum filter.
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- 2024
12. OrionNav: Online Planning for Robot Autonomy with Context-Aware LLM and Open-Vocabulary Semantic Scene Graphs
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Devarakonda, Venkata Naren, Goswami, Raktim Gautam, Kaypak, Ali Umut, Patel, Naman, Khorrambakht, Rooholla, Krishnamurthy, Prashanth, and Khorrami, Farshad
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Computer Science - Robotics - Abstract
Enabling robots to autonomously navigate unknown, complex, dynamic environments and perform diverse tasks remains a fundamental challenge in developing robust autonomous physical agents. These agents must effectively perceive their surroundings while leveraging world knowledge for decision-making. Although recent approaches utilize vision-language and large language models for scene understanding and planning, they often rely on offline processing, offboard compute, make simplifying assumptions about the environment and perception, limiting real-world applicability. We present a novel framework for real-time onboard autonomous navigation in unknown environments that change over time by integrating multi-level abstraction in both perception and planning pipelines. Our system fuses data from multiple onboard sensors for localization and mapping and integrates it with open-vocabulary semantics to generate hierarchical scene graphs from continuously updated semantic object map. The LLM-based planner uses these graphs to create multi-step plans that guide low-level controllers in executing navigation tasks specified in natural language. The system's real-time operation enables the LLM to adjust its plans based on updates to the scene graph and task execution status, ensuring continuous adaptation to new situations or when the current plan cannot accomplish the task, a key advantage over static or rule-based systems. We demonstrate our system's efficacy on a quadruped navigating dynamic environments, showcasing its adaptability and robustness in diverse scenarios.
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- 2024
13. AAAI Workshop on AI Planning for Cyber-Physical Systems -- CAIPI24
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Niggemann, Oliver, Biswas, Gautam, Diedrich, Alexander, Ehrhardt, Jonas, Heesch, René, and Widulle, Niklas
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Computer Science - Artificial Intelligence - Abstract
The workshop 'AI-based Planning for Cyber-Physical Systems', which took place on February 26, 2024, as part of the 38th Annual AAAI Conference on Artificial Intelligence in Vancouver, Canada, brought together researchers to discuss recent advances in AI planning methods for Cyber-Physical Systems (CPS). CPS pose a major challenge due to their complexity and data-intensive nature, which often exceeds the capabilities of traditional planning algorithms. The workshop highlighted new approaches such as neuro-symbolic architectures, large language models (LLMs), deep reinforcement learning and advances in symbolic planning. These techniques are promising when it comes to managing the complexity of CPS and have potential for real-world applications., Comment: This is the Proceedings of the AAAI Workshop on AI Planning for Cyber-Physical Systems - CAIPI24, which was held in Vancouver, CA, February 26, 2024
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- 2024
14. An Optimized H5 Hysteresis Current Control with Clamped Diodes in Transformer-less Grid-PV Inverter
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Phuyal, Sushil, Shrestha, Shashwot, Sharma, Swodesh, Subedi, Rachana, Panjiyar, Anil Kumar, and Gautam, Mukesh
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Electrical Engineering and Systems Science - Systems and Control - Abstract
With the rise of renewable energy penetration in the grid, photovoltaic (PV) panels are connected to the grid via inverters to supply solar energy. Transformer-less grid-tied PV inverters are gaining popularity because of their improved efficiency, reduced size, and lower costs. However, they can induce a path for leakage currents between the PV and the grid part due to the absence of galvanic isolation between them. This leads to serious electromagnetic interference, loss in efficiency and safety concerns. The leakage current is primarily influenced by the nature of the common mode voltage (CMV), which is determined by the switching techniques of the inverter. In this paper, a novel inverter topology of Hysteresis Controlled H5 with Two Clamping Diodes (HCH5-D2) has been derived. The HCH5-D2 topology helps to decouple the AC part (Grid) and DC part (PV) during the freewheeling to make the CMV constant and in turn, reduces the leakage current. Also, the additional diodes help to reduce the voltage spikes generated during the freewheeling period and maintain the CMV at a constant value. Finally, a 2.2kW grid-connected single-phase HCH5-D2 PV inverter system's MATLAB simulation has been presented with better results when compared with a traditional H4 inverter.
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- 2024
15. Open Science Practices by Early Career HCI Researchers: Perceptions, Challenges, and Benefits
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Chakravorti, Tatiana, Gautam, Sanjana, Silverstein, Priya, and Rajtmajer, Sarah M.
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Computer Science - Human-Computer Interaction - Abstract
Many fields of science, including Human-Computer Interaction (HCI), have heightened introspection in the wake of concerns around reproducibility and replicability of published findings. Notably, in recent years the HCI community has worked to implement policy changes and mainstream open science practices. Our work investigates early-career HCI researchers' perceptions of open science and engagement with best practices through 18 semi-structured interviews. Our findings highlight key barriers to the widespread adoption of data and materials sharing, and preregistration, namely: lack of clear incentives; cultural resistance; limited training; time constraints; concerns about intellectual property; and data privacy issues. We observe that small changes at major conferences like CHI could meaningfully impact community norms. We offer recommendations to address these barriers and to promote transparency and openness in HCI.
- Published
- 2024
16. The Ni isotopic composition of Ryugu reveals a common accretion region for carbonaceous chondrites
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Spitzer, Fridolin, Kleine, Thorsten, Burkhardt, Christoph, Hopp, Timo, Yokoyama, Tetsuya, Abe, Yoshinari, Aléon, Jérôme, Alexander, Conel M. O'D., Amari, Sachiko, Amelin, Yuri, Bajo, Ken-ichi, Bizzarro, Martin, Bouvier, Audrey, Carlson, Richard W., Chaussidon, Marc, Choi, Byeon-Gak, Dauphas, Nicolas, Davis, Andrew M., Di Rocco, Tommaso, Fujiya, Wataru, Fukai, Ryota, Gautam, Ikshu, Haba, Makiko K., Hibiya, Yuki, Hidaka, Hiroshi, Homma, Hisashi, Hoppe, Peter, Huss, Gary R., Ichida, Kiyohiro, Iizuka, Tsuyoshi, Ireland, Trevor R., Ishikawa, Akira, Itoh, Shoichi, Kawasaki, Noriyuki, Kita, Noriko T., Kitajima, Kouki, Komatani, Shintaro, Krot, Alexander N., Liu, Ming-Chang, Masuda, Yuki, Morita, Mayu, Moynier, Fréderic, Motomura, Kazuko, Nakai, Izumi, Nagashima, Kazuhide, Nguyen, Ann, Nittler, Larry, Onose, Morihiko, Pack, Andreas, Park, Changkun, Piani, Laurette, Qin, Liping, Russell, Sara S., Sakamoto, Naoya, Schönbächler, Maria, Tafla, Lauren, Tang, Haolan, Terada, Kentaro, Terada, Yasuko, Usui, Tomohiro, Wada, Sohei, Wadhwa, Meenakshi, Walker, Richard J., Yamashita, Katsuyuki, Yin, Qing-Zhu, Yoneda, Shigekazu, Young, Edward D., Yui, Hiroharu, Zhang, Ai-Cheng, Nakamura, Tomoki, Naraoka, Hiroshi, Noguchi, Takaaki, Okazaki, Ryuji, Sakamoto, Kanako, Yabuta, Hikaru, Abe, Masanao, Miyazaki, Akiko, Nakato, Aiko, Nishimura, Masahiro, Okada, Tatsuaki, Yada, Toru, Yogata, Kasumi, Nakazawa, Satoru, Saiki, Takanao, Tanaka, Satoshi, Terui, Fuyuto, Tsuda, Yuichi, Watanabe, Sei-ichiro, Yoshikawa, Makoto, Tachibana, Shogo, and Yurimoto, Hisayoshi
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Astrophysics - Earth and Planetary Astrophysics - Abstract
The isotopic compositions of samples returned from Cb-type asteroid Ryugu and Ivuna-type (CI) chondrites are distinct from other carbonaceous chondrites, which has led to the suggestion that Ryugu and CI chondrites formed in a different region of the accretion disk, possibly around the orbits of Uranus and Neptune. We show that, like for Fe, Ryugu and CI chondrites also have indistinguishable Ni isotope anomalies, which differ from those of other carbonaceous chondrites. We propose that this unique Fe and Ni isotopic composition reflects different accretion efficiencies of small FeNi metal grains among the carbonaceous chondrite parent bodies. The CI chondrites incorporated these grains more efficiently, possibly because they formed at the end of the disk's lifetime, when planetesimal formation was also triggered by photoevaporation of the disk. Isotopic variations among carbonaceous chondrites may thus reflect fractionation of distinct dust components from a common reservoir, implying CI chondrites and Ryugu may have formed in the same region of the accretion disk as other carbonaceous chondrites., Comment: Published open access in Science Advances
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- 2024
- Full Text
- View/download PDF
17. Space-Projected Thermal Conductivity
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Gautam, A., Lee, Y. G., Ugwumadu, C., Nepal, K., Nakhmanson, S., and Drabold, D. A.
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Condensed Matter - Materials Science - Abstract
With the rapid advancement of high-power computing and electronic technologies, understanding thermal conductivity in materials has become increasingly important. This study presents a novel method called the Space-Projected Thermal Conductivity (SPTC) that can predict thermal activity at the atomic scale, leveraging the Green-Kubo thermal transport equations. We demonstrate the effectiveness of this approach on crystalline and amorphous carbon-based structures, paracrystalline and amorphous silicon, and grain boundaries in silicon-germanium alloys. The results highlight the potential of our method to provide new insights into the thermal behavior of materials, offering a promising avenue for materials design and performance optimization., Comment: 7 pages, 8 figures, Initial submission to PSS (RRL)
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- 2024
18. Symmetry-controlled orbital Hall effect in IrO$_2$
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Patton, Michael, Go, Dongwook, Pharis, Daniel A., Huang, Xiaoxi, Gurung, Gautam, Tsymbal, Evgeny Y., Ralph, Daniel C., Rzchowski, Mark S., Mokrousov, Yuriy, and Eom, Chang-Beom
- Subjects
Condensed Matter - Materials Science - Abstract
Recent discovery of orbital currents in several material platforms including light element metals has opened new possibilities for exploring novel transport phenomena and applications to spin-orbitronic devices. These orbital currents, similar to spin currents, have the ability to generate torque on adjacent magnetic layers, opening a new avenue for efficient spintronic devices. However, separating spin and orbital currents has been one of the major challenges. Here, we show evidence for large conventional as well as unconventional spin and orbital currents in IrO$_2$ and disentangle them by crystal symmetry. We study the anisotropic spin and orbital Hall effects in IrO$_2$ (001), (100), and (111) orientations and find unconventional z-polarized orbital torques using angular spin torque ferromagnetic resonance of IrO$_2$/Ni heterostructures, which are in agreement regarding the relative signs with theoretical calculations of spin and orbital Hall conductivity. This work provides a promising route towards highly efficient low power spintronic and orbitronic devices in oxide heterostructures.
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- 2024
19. Driving the Berry phase anomalous Hall effect in a noncollinear antiferromagnet by domain manipulation
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Yao, Yuchuan, Pal, Pratap, Campbell, Neil G., Gurung, Gautam, Johnson, Roger D., Manuel, Pascal, Tsymbal, Evgeny Y., Rzchowski, Mark S., and Eom, Chang-Beom
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Condensed Matter - Materials Science ,Condensed Matter - Strongly Correlated Electrons - Abstract
The emergence of anomalous Hall effects (AHE) in antiferromagnets presents an intriguing phenomenon with potential spintronic device applications due to their ultrafast switching dynamics. Mn3NiN antiperovskite stands out as a promising candidate owing to its noncollinear antiferromagnetism. In this study, we report a significant AHE observed in epitaxial Mn3NiN thin films below the N\'eel temperature, comparable to those observed in typical ferromagnets. Through a combination of magnetometry, neutron diffraction and ab-initio data analyses, we propose that the substantial AHE can be attributed to the non-vanishing Berry curvature arising from the {\Gamma}4g-type spin structure, coupled with uncompensated magnetic domains featuring a weak canted moment. This coupling, due to robust antiferromagnetic domains, enables deterministic detection and switching of AHE via the application of a magnetic field.
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- 2024
20. Hate Speech Detection Using Cross-Platform Social Media Data In English and German Language
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Shahi, Gautam Kishore and Majchrzak, Tim A.
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Computer Science - Computation and Language ,Computer Science - Artificial Intelligence ,Computer Science - Social and Information Networks - Abstract
Hate speech has grown into a pervasive phenomenon, intensifying during times of crisis, elections, and social unrest. Multiple approaches have been developed to detect hate speech using artificial intelligence, but a generalized model is yet unaccomplished. The challenge for hate speech detection as text classification is the cost of obtaining high-quality training data. This study focuses on detecting bilingual hate speech in YouTube comments and measuring the impact of using additional data from other platforms in the performance of the classification model. We examine the value of additional training datasets from cross-platforms for improving the performance of classification models. We also included factors such as content similarity, definition similarity, and common hate words to measure the impact of datasets on performance. Our findings show that adding more similar datasets based on content similarity, hate words, and definitions improves the performance of classification models. The best performance was obtained by combining datasets from YouTube comments, Twitter, and Gab with an F1-score of 0.74 and 0.68 for English and German YouTube comments.
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- 2024
21. Membership Inference Attacks Cannot Prove that a Model Was Trained On Your Data
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Zhang, Jie, Das, Debeshee, Kamath, Gautam, and Tramèr, Florian
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Computer Science - Machine Learning ,Computer Science - Cryptography and Security - Abstract
We consider the problem of a training data proof, where a data creator or owner wants to demonstrate to a third party that some machine learning model was trained on their data. Training data proofs play a key role in recent lawsuits against foundation models trained on web-scale data. Many prior works suggest to instantiate training data proofs using membership inference attacks. We argue that this approach is fundamentally unsound: to provide convincing evidence, the data creator needs to demonstrate that their attack has a low false positive rate, i.e., that the attack's output is unlikely under the null hypothesis that the model was not trained on the target data. Yet, sampling from this null hypothesis is impossible, as we do not know the exact contents of the training set, nor can we (efficiently) retrain a large foundation model. We conclude by offering two paths forward, by showing that data extraction attacks and membership inference on special canary data can be used to create sound training data proofs.
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- 2024
22. FlashMix: Fast Map-Free LiDAR Localization via Feature Mixing and Contrastive-Constrained Accelerated Training
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Goswami, Raktim Gautam, Patel, Naman, Krishnamurthy, Prashanth, and Khorrami, Farshad
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Computer Science - Computer Vision and Pattern Recognition - Abstract
Map-free LiDAR localization systems accurately localize within known environments by predicting sensor position and orientation directly from raw point clouds, eliminating the need for large maps and descriptors. However, their long training times hinder rapid adaptation to new environments. To address this, we propose FlashMix, which uses a frozen, scene-agnostic backbone to extract local point descriptors, aggregated with an MLP mixer to predict sensor pose. A buffer of local descriptors is used to accelerate training by orders of magnitude, combined with metric learning or contrastive loss regularization of aggregated descriptors to improve performance and convergence. We evaluate FlashMix on various LiDAR localization benchmarks, examining different regularizations and aggregators, demonstrating its effectiveness for rapid and accurate LiDAR localization in real-world scenarios. The code is available at https://github.com/raktimgg/FlashMix.
- Published
- 2024
23. Enhancing Structured-Data Retrieval with GraphRAG: Soccer Data Case Study
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Sepasdar, Zahra, Gautam, Sushant, Midoglu, Cise, Riegler, Michael A., and Halvorsen, Pål
- Subjects
Computer Science - Information Retrieval ,Computer Science - Artificial Intelligence ,Computer Science - Databases ,H.2 ,H.3 ,E.1 ,E.2 - Abstract
Extracting meaningful insights from large and complex datasets poses significant challenges, particularly in ensuring the accuracy and relevance of retrieved information. Traditional data retrieval methods such as sequential search and index-based retrieval often fail when handling intricate and interconnected data structures, resulting in incomplete or misleading outputs. To overcome these limitations, we introduce Structured-GraphRAG, a versatile framework designed to enhance information retrieval across structured datasets in natural language queries. Structured-GraphRAG utilizes multiple knowledge graphs, which represent data in a structured format and capture complex relationships between entities, enabling a more nuanced and comprehensive retrieval of information. This graph-based approach reduces the risk of errors in language model outputs by grounding responses in a structured format, thereby enhancing the reliability of results. We demonstrate the effectiveness of Structured-GraphRAG by comparing its performance with that of a recently published method using traditional retrieval-augmented generation. Our findings show that Structured-GraphRAG significantly improves query processing efficiency and reduces response times. While our case study focuses on soccer data, the framework's design is broadly applicable, offering a powerful tool for data analysis and enhancing language model applications across various structured domains.
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- 2024
24. Tidally Heated Sub-Neptunes, Refined Planetary Compositions, and Confirmation of a Third Planet in the TOI-1266 System
- Author
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Greklek-McKeon, Michael, Vissapragada, Shreyas, Knutson, Heather A., Fukui, Akihiko, Saidel, Morgan, Barrientos, Jonathan Gomez, Levine, W. Garrett, Behmard, Aida, Batygin, Konstantin, Chachan, Yayaati, Vasisht, Gautam, Hu, Renyu, Cloutier, Ryan, Latham, David, López-Morales, Mercedes, Vanderburg, Andrew, Heffner, Carolyn, Nied, Paul, Milburn, Jennifer, Wilson, Isaac, Roderick, Diana, Koviak, Kathleen, Barlow, Tom, Stone, John F., Kiman, Rocio, Korth, Judith, de Leon, Jerome P., Fukuda, Izuru, Hayashi, Yuya, Ikoma, Masahiro, Ikuta, Kai, Isogai, Keisuke, Kawai, Yugo, Kawauchi, Kiyoe, Kusakabe, Nobuhiko, Livingston, John H., Mori, Mayuko, Narita, Norio, Tamura, Motohide, Watanabe, Noriharu, and Fernández-Rodríguez, Gareb
- Subjects
Astrophysics - Earth and Planetary Astrophysics - Abstract
TOI-1266 is a benchmark system of two temperate ($<$ 450 K) sub-Neptune-sized planets orbiting a nearby M dwarf exhibiting a rare inverted architecture with a larger interior planet. In this study, we characterize transit timing variations (TTVs) in the TOI-1266 system using high-precision ground-based follow-up and new TESS data. We confirm the presence of a third exterior non-transiting planet, TOI-1266 d (P = 32.5 d, $M_d$ = 3.68$^{+1.05}_{-1.11} M_{\oplus}$), and combine the TTVs with archival radial velocity (RV) measurements to improve our knowledge of the planetary masses and radii. We find that, consistent with previous studies, TOI-1266 b ($R_b$ = 2.52 $\pm$ 0.08 $R_{\oplus}$, $M_b$ = 4.46 $\pm$ 0.69 $M_{\oplus}$) has a low bulk density requiring the presence of a hydrogen-rich envelope, while TOI-1266 c ($R_c$ = 1.98 $\pm$ 0.10 $R_{\oplus}$, $M_c$ = 3.17 $\pm$ 0.76 $M_{\oplus}$) has a higher bulk density that can be matched by either a hydrogen-rich or water-rich envelope. Our new dynamical model reveals that this system is arranged in a rare configuration with the inner and outer planets located near the 3:1 period ratio with a non-resonant planet in between them. Our dynamical fits indicate that the inner and outer planet have significantly nonzero eccentricities ($e_b + e_d = 0.076^{+0.029}_{-0.019}$), suggesting that TOI-1266 b may have an inflated envelope due to tidal heating. Finally, we explore the corresponding implications for the formation and long-term evolution of the system, which contains two of the most favorable cool ($<$ 500 K) sub-Neptunes for atmospheric characterization with JWST., Comment: 36 pages, 19 figures, 5 tables, submitted to The Astronomical Journal
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- 2024
25. Quasielastic $\overrightarrow{^{3}\mathrm{He}}(\overrightarrow{e},{e'})$ Asymmetry in the Threshold Region
- Author
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Nycz, M., Armstrong, W., Averett, T., Gayoso, C. Ayerbe, Bai, X., Bane, J., Barcus, S., Benesch, J., Bhatt, H., Bhetuwal, D., Biswas, D., Camsonne, A., Cates, G., Chen, J-P., Chen, J., Chen, M., Cotton, C., Dalton, M-M., Deltuva, A., Deur, A., Dhital, B., Duran, B., Dusa, S. C., Fernando, I., Fuchey, E., Gamage, B., Gao, H., Gaskell, D., Gautam, T., Gauthier, N., Golak, J., Hansen, J. -O., Hauenstein, F., Henry, W., Higinbotham, D. W., Huber, G., Jantzi, C., Jia, S., Jin, K., Jones, M., Joosten, S., Karki, A., Karki, B., Katugampola, S., Kay, S., Keppel, C., King, E., King, P., Korsch, W., Kumar, V., Li, R., Li, S., Li, W., Mack, D., Malace, S., Markowitz, P., Matter, J., McCaughan, M., Meziani, Z-E., Michaels, R., Mkrtchyan, A., Mkrtchyan, H., Morean, C., Nelyubin, V., Niculescu, G., Niculescu, M., Peng, C., Premathilake, S., Puckett, A., Rathnayake, A., Rehfuss, M., Reimer, P., Riley, G., Roblin, Y., Roche, J., Roy, M., Sauer, P. U., Scopeta, S., Satnik, M., Sawatzky, B., Seeds, S., Širca, S. S., Skibiński, R., Smith, G., Sparveris, N., Szumila-Vance, H., Tadepalli, A., Tadevosyan, V., Tian, Y., Usman, A., Voskanyan, H., Witala, H., Wood, S., Yale, B., Yero, C., Yoon, A., Zhang, J., Zhao, Z., Zheng, X., and Zhou, J.
- Subjects
Nuclear Experiment - Abstract
A measurement of the double-spin asymmetry from electron-$^{3}$He scattering in the threshold region of two- and three-body breakup of $^{3}$He was performed at Jefferson Lab, for Q$^{2}$ values of 0.1 and 0.2 (GeV/$c$)$^{2}$. The results of this measurement serve as a stringent test of our understanding of few-body systems. When compared with calculations from plane wave impulse approximation and Faddeev theory, we found that the Faddeev calculations, which use modern nuclear potentials and prescriptions for meson-exchange currents, demonstrate an overall good agreement with data.
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- 2024
26. Transformer based time series prediction of the maximum power point for solar photovoltaic cells
- Author
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Agrawal, Palaash, Bansal, Hari Om, Gautam, Aditya R., Mahela, Om Prakash, and Khan, Baseem
- Subjects
Electrical Engineering and Systems Science - Systems and Control ,Computer Science - Machine Learning - Abstract
This paper proposes an improved deep learning based maximum power point tracking (MPPT) in solar photovoltaic cells considering various time series based environmental inputs. Generally, artificial neural network based MPPT algorithms use basic neural network architectures and inputs which do not represent the ambient conditions in a comprehensive manner. In this article, the ambient conditions of a location are represented through a comprehensive set of environmental features. Furthermore, the inclusion of time based features in the input data is considered to model cyclic patterns temporally within the atmospheric conditions leading to robust modeling of the MPPT algorithm. A transformer based deep learning architecture is trained as a time series prediction model using multidimensional time series input features. The model is trained on a dataset containing typical meteorological year data points of ambient weather conditions from 50 locations. The attention mechanism in the transformer modules allows the model to learn temporal patterns in the data efficiently. The proposed model achieves a 0.47% mean average percentage error of prediction on non zero operating voltage points in a test dataset consisting of data collected over a period of 200 consecutive hours resulting in the average power efficiency of 99.54% and peak power efficiency of 99.98%. The proposed model is validated through real time simulations. The proposed model performs power point tracking in a robust, dynamic, and nonlatent manner, over a wide range of atmospheric conditions., Comment: Published June 2022, in Energy Science and Engineering, Volume10, Issue9, Pages 3397-3410
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- 2024
- Full Text
- View/download PDF
27. New Measurements of the Deuteron to Proton F2 Structure Function Ratio
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Biswas, Debaditya, Gonzalez, Fernando Araiza, Henry, William, Karki, Abishek, Morean, Casey, Nadeeshani, Sooriyaarachchilage, Sun, Abel, Abrams, Daniel, Ahmed, Zafar, Aljawrneh, Bashar, Alsalmi, Sheren, Ambrose, George, Armstrong, Whitney, Asaturyan, Arshak, Assumin-Gyimah, Kofi, Gayoso, Carlos Ayerbe, Bandari, Anashe, Basnet, Samip, Berdnikov, Vladimir, Bhatt, Hem, Bhetuwal, Deepak, Boeglin, Werner, Bosted, Peter, Brash, Edward, Bukhari, Masroor, Chen, Haoyu, Chen, Jian-Ping, Chen, Mingyu, Christy, Michael Eric, Dusa, Silviu Covrig, Craycraft, Kayla, Danagoulian, Samuel, Day, Donal, Diefenthaler, Markus, Dlamini, Mongi, Dunne, James, Duran, Burcu, Dutta, Dipangkar, Ent, Rolf, Evans, Rory, Fenker, Howard, Fomin, Nadia, Fuchey, Eric, Gaskell, David, Gautam, Thir Narayan, Hansen, Jens-Ole, Hauenstein, Florian, Hernandez, A., Horn, Tanja, Huber, Garth, Jones, Mark, Joosten, Sylvester, Kabir, Md Latiful, Keppel, Cynthia, Khanal, Achyut, King, Paul, Kinney, Edward, Kohl, Michael, Lashley-Colthirst, Nathaniel, Li, Shujie, Li, Wenliang, Liyanage, Anusha Habarakada, Mack, David, Malace, Simona, Markowitz, Pete, Matter, John, Meekins, David, Michaels, Robert, Mkrtchyan, Arthur, Mkrtchyan, Hamlet, Moore, Zae, Nazeer, S. J., Nanda, Shirsendu, Niculescu, Gabriel, Niculescu, Maria, Nguyen, Huong, Nuruzzaman, Nuruzzaman, Pandey, Bishnu, Park, Sanghwa, Pooser, Eric, Puckett, Andrew, Rehfuss, Melanie, Reinhold, Joerg, Sawatzky, Bradley, Smith, G., Szumila-Vance, Holly, Tadepalli, Arun, Tadevosyan, Vardan, Trotta, Richard, Wood, Stephen, Yero, Carlos, and Zhang, Jinlong
- Subjects
High Energy Physics - Experiment - Abstract
Nucleon structure functions, as measured in lepton-nucleon scattering, have historically provided a critical observable in the study of partonic dynamics within the nucleon. However, at very large parton momenta it is both experimentally and theoretically challenging to extract parton distributions due to the probable onset of non-perturbative contributions and the unavailability of high precision data at critical kinematics. Extraction of the neutron structure and the d-quark distribution have been further challenging due to the necessity of applying nuclear corrections when utilizing scattering data from a deuteron target to extract free neutron structure. However, a program of experiments has been carried out recently at the energy-upgraded Jefferson Lab electron accelerator aimed at significantly reducing the nuclear correction uncertainties on the d-quark distribution function at large partonic momentum. This allows leveraging the vast body of deuterium data covering a large kinematic range to be utilized for d-quark parton distribution function extraction. We present new data from experiment E12-10-002 carried out in Jefferson Lab Hall C on the deuteron to proton cross-section ratio at large BJorken-x. These results significantly improve the precision of existing data, and provide a first look at the expected impact on quark distributions extracted from global parton distribution function fits.
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- 2024
28. The discrete analogue of the Gaussian
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Chinta, Gautam, Jorgenson, Jay, Karlsson, Anders, and Smajlović, Lejla
- Subjects
Mathematical Physics ,Mathematics - Probability ,81Q99, 81T25, 35Gxx, 58J35, 60F05, 68P27 - Abstract
This paper illustrates the utility of the heat kernel on $\mathbb{Z}$ as the discrete analogue of the Gaussian density function. It is the two-variable function $K_{\mathbb{Z}}(t,x)=e^{-2t}I_{x}(2t)$ involving a Bessel function and variables $x\in\mathbb{Z}$ and real $t\geq 0$. Like its classic counterpart it appears in many mathematical and physical contexts and has a wealth of applications. Some of these will be reviewed here, concerning Bessel integrals, trigonometric sums, hypergeometric functions and asymptotics of discrete models appearing in statistical and quantum physics. Moreover, we prove a new local limit theorem for sums of integer-valued random variables, obtain novel special values of the spectral zeta function of Bethe lattices, and provide a discussion on how $e^{-2t}I_{x}(2t)$ could be useful in differential privacy., Comment: 21 pages, 2 figures
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- 2024
29. Investigation of magnetic and transport properties of GdSbSe
- Author
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Gautam, Aarti, Mishra, Prabuddha Kant, Banerjee, Souvik, Sundaresan, A., and Ganguli, Ashok Kumar
- Subjects
Condensed Matter - Strongly Correlated Electrons - Abstract
We report the detailed investigation of the magnetic, transport, and magnetocaloric effects of GdSbSe by magnetic susceptibility $\chi(T)$, isothermal magnetization $M(H)$, resistivity $\rho(T, H)$, and heat capacity $C_p(T)$ measurements, crystallizing in the ZrSiS-type tetragonal crystal system with space group $P4/nmm$. Temperature-dependent magnetic susceptibility measurements revealed long-range antiferromagnetic ordering with two additional magnetic anomalies below N\'eel temperature ($T_N$ $\approx$ 8.6 K), corroborated through magnetocaloric and specific heat studies. Isothermal magnetization measurements unveil hidden metamagnetic signatures through a clear deviation from linearity. In addition, the enhanced value of the Sommerfeld coefficient ($\gamma$ = 152(5) mJ/ mol K$^2$) suggests strong electronic correlations in GdSbSe. The entropy of magnetization derived from magnetic isotherms unfolds the field-induced transition from Inverse magnetocaloric Effect (IMCE) to Conventional MCE. The detailed transport properties indicate a semimetallic behavior, strongly coupled with magnetic order. Deviations from Kohler's rule and non-linear Hall resistivity anticipate the possibility of Dirac-like dispersion with non-trivial characteristics., Comment: 10 pages, 9 Figures
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- 2024
30. The $\delta$ Scuti stars of the Cep--Her Complex. I: Pulsator fraction, rotation, asteroseismic large spacings, and the $\nu_{\rm max}$ relation
- Author
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Murphy, Simon J., Bedding, Timothy R., Gautam, Anuj, Kerr, Ronan P., and Mani, Prasad
- Subjects
Astrophysics - Solar and Stellar Astrophysics - Abstract
We identify delta Scuti pulsators amongst members of the recently-discovered Cep--Her Complex using light curves from the Transiting Exoplanet Survey Satellite (TESS). We use Gaia colours and magnitudes to isolate a subsample of provisional Cep--Her members that are located in a narrow band on the colour--magnitude diagram compatible with the zero-age main sequence. The $\delta$ Sct pulsator fraction amongst these stars peaks at 100% and we describe a trend of higher pulsator fractions for younger stellar associations. We use four methods to measure the frequency of maximum amplitude or power, $\nu_{\rm max}$, to minimise methodological bias and we demonstrate their sound performance. The $\nu_{\rm max}$ measurements display a correlation with effective temperature, but with scatter that is too large for the relation to be useful. We find two ridges in the $\nu_{\rm max}$--$T_{\rm eff}$ diagram, one of which appears to be the result of rapid rotation causing stars to pulsate in low-order modes. We measure the $\nu_{\rm max}$ values of $\delta$ Sct stars in four other clusters or associations of similar age (Trumpler 10, the Pleiades, NGC 2516, and Praesepe) and find similar behaviour with $T_{\rm eff}$. Using \'echelle diagrams we measure the asteroseismic large spacing, $\Delta\nu$, for 70 stars, and find a correlation between $\Delta\nu$, rotation, and luminosity that allows rapid rotators seen at low inclinations to be distinguished from slow rotators. We find that rapid rotators are more likely than slow rotators to pulsate, but they do so with less regular pulsation patterns. We also investigate the reliability of Gaia's vbroad measurement for A-type stars, finding that it is mostly accurate but underestimates $v\sin i$ for slow rotators ($v\sin i < 50$ km.s$^{-1}$) by 10--15%., Comment: 19 pages, or 12 without end-matter. Accepted in MNRAS. Supplementary online material will be made available via the MNRAS webpage and CDS. Version 2 has an updated reference list
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- 2024
31. Residual Diffusivity for Noisy Bernoulli Maps
- Author
-
Iyer, Gautam and Nolen, James
- Subjects
Mathematics - Dynamical Systems ,Mathematics - Analysis of PDEs ,Mathematics - Probability ,60J05 (Primary) 37A25, 35B27 (Secondary) - Abstract
Consider a discrete time Markov process $X^\varepsilon$ on $\mathbb R^d$ that makes a deterministic jump prescribed by a map $\varphi \colon \mathbb R^d \to \mathbb R^d$, and then takes a small Gaussian step of variance $\varepsilon^2$. For certain chaotic maps $\varphi$, the effective diffusivity of $X^\varepsilon$ may be bounded away from $0$ as $\varepsilon \to 0$. This is known as residual diffusivity, and in this paper we prove residual diffusivity occurs for a class of maps $\varphi$ obtained from piecewise affine expanding Bernoulli maps., Comment: 24 pages, 2 figures
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- 2024
32. Star cluster formation from turbulent clumps. IV. Protoplanetary disc evolution
- Author
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Gautam, Aayush, Farias, Juan P., and Tan, Jonathan C.
- Subjects
Astrophysics - Astrophysics of Galaxies ,Astrophysics - Earth and Planetary Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
Most stars are born in the crowded environments of gradually forming star clusters. Dynamical interactions between close-passing stars and the evolving UV radiation fields from proximate massive stars are expected to sculpt the protoplanetary discs in these clusters, potentially contributing to the diversity of planetary systems that we observe. Here, we investigate the impact of cluster environment on disc demographics by implementing simple protoplanetary disc evolution models within $N$-body simulations of gradual star cluster formation. We consider a range of star formation efficiency per free-fall time, $\epsilon_{\rm ff}$, and mass surface density of the natal cloud environment, $\Sigma_{\rm cl}$, both of which affect the overall duration of cluster formation. We track the interaction history of all stars to estimate the dynamical truncation of the discs around stars involved in close encounters. We also track external photoevaporation of the discs due to the ionizing radiation field of the nearby high- and intermediate-mass ($> 5 M_\odot$) stars. We find that $\epsilon_{\rm ff}$, $\Sigma_{\rm cl}$, and the degree of primordial binarity have major influences on the masses and radii of the disc population. In particular, external photo-evaporation has a greater impact than dynamical interactions in determining the fate of discs in our clusters., Comment: Submitted to MNRAS. 16 pages, 9 figures. Comments welcome
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- 2024
33. SuperCoder2.0: Technical Report on Exploring the feasibility of LLMs as Autonomous Programmer
- Author
-
Gautam, Anmol, Kumar, Kishore, Jha, Adarsh, NS, Mukunda, and Bhola, Ishaan
- Subjects
Computer Science - Software Engineering ,Computer Science - Artificial Intelligence - Abstract
We present SuperCoder2.0, an advanced autonomous system designed to enhance software development through artificial intelligence. The system combines an AI-native development approach with intelligent agents to enable fully autonomous coding. Key focus areas include a retry mechanism with error output traceback, comprehensive code rewriting and replacement using Abstract Syntax Tree (ast) parsing to minimize linting issues, code embedding technique for retrieval-augmented generation, and a focus on localizing methods for problem-solving rather than identifying specific line numbers. The methodology employs a three-step hierarchical search space reduction approach for code base navigation and bug localization:utilizing Retrieval Augmented Generation (RAG) and a Repository File Level Map to identify candidate files, (2) narrowing down to the most relevant files using a File Level Schematic Map, and (3) extracting 'relevant locations' within these files. Code editing is performed through a two-part module comprising CodeGeneration and CodeEditing, which generates multiple solutions at different temperature values and replaces entire methods or classes to maintain code integrity. A feedback loop executes repository-level test cases to validate and refine solutions. Experiments conducted on the SWE-bench Lite dataset demonstrate SuperCoder2.0's effectiveness, achieving correct file localization in 84.33% of cases within the top 5 candidates and successfully resolving 34% of test instances. This performance places SuperCoder2.0 fourth globally on the SWE-bench leaderboard. The system's ability to handle diverse repositories and problem types highlights its potential as a versatile tool for autonomous software development. Future work will focus on refining the code editing process and exploring advanced embedding models for improved natural language to code mapping.
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- 2024
34. Single-stage TTS with Masked Audio Token Modeling and Semantic Knowledge Distillation
- Author
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Gállego, Gerard I., Fejgin, Roy, Yeh, Chunghsin, Liu, Xiaoyu, and Bhattacharya, Gautam
- Subjects
Computer Science - Sound ,Computer Science - Artificial Intelligence ,Electrical Engineering and Systems Science - Audio and Speech Processing ,Electrical Engineering and Systems Science - Signal Processing - Abstract
Audio token modeling has become a powerful framework for speech synthesis, with two-stage approaches employing semantic tokens remaining prevalent. In this paper, we aim to simplify this process by introducing a semantic knowledge distillation method that enables high-quality speech generation in a single stage. Our proposed model improves speech quality, intelligibility, and speaker similarity compared to a single-stage baseline. Although two-stage systems still lead in intelligibility, our model significantly narrows the gap while delivering comparable speech quality. These findings showcase the potential of single-stage models to achieve efficient, high-quality TTS with a more compact and streamlined architecture., Comment: Demo page: see https://narsistts.github.io
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- 2024
35. Dynamic landscapes and statistical limits on growth during cell fate specification
- Author
-
Reddy, Gautam
- Subjects
Physics - Biological Physics ,Quantitative Biology - Cell Behavior ,Quantitative Biology - Tissues and Organs - Abstract
The complexity of gene regulatory networks in multicellular organisms makes interpretable low-dimensional models highly desirable. An attractive geometric picture, attributed to Waddington, visualizes the differentiation of a cell into diverse functional types as gradient flow on a dynamic potential landscape, but it is unclear under what biological constraints this metaphor is mathematically precise. Here, we show that growth-maximizing regulatory strategies that guide a single cell to a target distribution of cell types are described by time-dependent potential landscapes, under certain generic growth-control tradeoffs. Our analysis leads to a sharp bound on the time it takes for a population to grow to a target distribution of a certain size. We show how the framework can be used to compute Waddington-like epigenetic landscapes and growth curves in an illustrative model of growth and differentiation. The theory suggests a conceptual link between nonequilibrium thermodynamics and cellular decision-making during development.
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- 2024
36. Characterisation of analogue MAPS fabricated in 65 nm technology for the ALICE ITS3
- Author
-
Gautam, Kunal and Kumar, Ajit
- Subjects
Physics - Instrumentation and Detectors ,High Energy Physics - Experiment - Abstract
The ALICE ITS3 project foresees the use of ultra-light MAPS, developed in the 65 nm imaging process, for the vertex detector in the ALICE experiment at the LHC to drastically improve the vertexing performance. This new development, initiated by an international consortium of the ALICE ITS3 collaboration and the CERN EP R&D project, enhances the overall MAPS performance. Small-scale prototypes are designed to study the analogue properties of the TPSCo 65 nm technology and compare the charge collection performance in different processes, pitches, pixel geometries, and irradiation levels. Recent results from lab and test-beam characterisation detailing the efficiency and the spatial resolution of the APTS with different pixel geometries and pitches satisfy the ALICE ITS3 requirements. A quantitative evolution of the charge collection and sharing among pixels is evident in the CE-65 with different in-pixel readouts. Attaining a spatial resolution better than 3 $\mu$m with a 10 $\mu$m pitch and over 99% efficiency in the moderate irradiation environment of ALICE also supports the viability of using 65 nm MAPS for FCC-ee vertex detectors.
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- 2024
- Full Text
- View/download PDF
37. Investigating Ionic Diffusivity in Amorphous Solid Electrolytes using Machine Learned Interatomic Potentials
- Author
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Seth, Aqshat, Kulkarni, Rutvij Pankaj, and Gautam, Gopalakrishnan Sai
- Subjects
Condensed Matter - Materials Science - Abstract
Investigating Li$^+$ transport within the amorphous lithium phosphorous oxynitride (LiPON) framework, especially across a Li||LiPON interface, has proven challenging due to its amorphous nature and varying stoichiometry, necessitating large supercells and long timescales for computational models. Notably, machine learned interatomic potentials (MLIPs) can combine the computational speed of classical force fields with the accuracy of density functional theory (DFT), making them the ideal tool for modelling such amorphous materials. Thus, in this work, we train and validate the neural equivariant Interatomic potential (NequIP) framework on a comprehensive DFT-based dataset consisting of 13,454 chemically relevant structures to describe LiPON. With an optimized training (validation) energy and force mean absolute errors of 5.5 (6.1) meV/atom and 13.6 (13.2) meV/{\AA}, respectively, we employ the trained potential in model Li-transport in both bulk LiPON and across a Li||LiPON interface. Amorphous LiPON structures generated by the optimized potential do resemble those generated by ab initio molecular dynamics, with N being incorporated on non-bridging apical and bridging sites. Subsequent analysis of Li$^+$ diffusivity in the bulk LiPON structures indicates broad agreement with computational and experimental literature so far. Further, we investigate the anisotropy in Li$^+$ transport across the Li(110)||LiPON interface, where we observe Li-transport across the interface to be one order-of-magnitude slower than Li-motion within the bulk Li and LiPON phases. Nevertheless, we note that this anisotropy of Li-transport across the interface is minor and do not expect it to cause any significant impedance buildup. Finally, our work highlights the efficiency of MLIPs in enabling high-fidelity modelling of complex non-crystalline systems over large length and time scales.
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- 2024
38. WinoPron: Revisiting English Winogender Schemas for Consistency, Coverage, and Grammatical Case
- Author
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Gautam, Vagrant, Steuer, Julius, Bingert, Eileen, Johns, Ray, Lauscher, Anne, and Klakow, Dietrich
- Subjects
Computer Science - Computation and Language - Abstract
While measuring bias and robustness in coreference resolution are important goals, such measurements are only as good as the tools we use to measure them. Winogender Schemas (Rudinger et al., 2018) are an influential dataset proposed to evaluate gender bias in coreference resolution, but a closer look reveals issues with the data that compromise its use for reliable evaluation, including treating different pronominal forms as equivalent, violations of template constraints, and typographical errors. We identify these issues and fix them, contributing a new dataset: WinoPron. Using WinoPron, we evaluate two state-of-the-art supervised coreference resolution systems, SpanBERT, and five sizes of FLAN-T5, and demonstrate that accusative pronouns are harder to resolve for all models. We also propose a new method to evaluate pronominal bias in coreference resolution that goes beyond the binary. With this method, we also show that bias characteristics vary not just across pronoun sets (e.g., he vs. she), but also across surface forms of those sets (e.g., him vs. his)., Comment: Workshop on Computational Models of Reference, Anaphora and Coreference at EMNLP 2024
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- 2024
39. A regularity theorem for fully nonlinear maximally subelliptic PDE
- Author
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Memana, Gautam Neelakantan
- Subjects
Mathematics - Analysis of PDEs ,35H20, 35G10, 35G20 - Abstract
We prove a sharp interior regularity theorem for fully nonlinear maximally subelliptic PDE in non-isotropic Sobolev spaces adapted to maximally subelliptic operators. This result complements the regularity theorem proven by Street for adapted Zygmund-H\"older spaces. This also recovers the classical regularity theorem for fully nonlinear elliptic differential operators for classical Sobolev spaces. We also obtain a sharp interior regularity theorem for fully nonlinear maximally subelliptic PDE in isotropic Sobolev spaces., Comment: 68 pages, no pages
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- 2024
40. Non-smooth paths having unit speed with respect to the Kobayashi metric
- Author
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Bharali, Gautam and Masanta, Rumpa
- Subjects
Mathematics - Metric Geometry ,Mathematics - Complex Variables ,32F45, 32Q45 (Primary) 53C23 (Secondary) - Abstract
In this paper, we investigate the question of whether a non-constant absolutely continuous path can be reparametrised as being unit speed with respect to the Kobayashi metric. Even when the answer is "Yes," which isn't always the case, its proof involves some subtleties. We answer the above question and discuss a small application to Kobayashi geometry., Comment: 8 pages; comments welcome!
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- 2024
41. The Kneser--Poulsen phenomena for entropy
- Author
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Aishwarya, Gautam and Li, Dongbin
- Subjects
Mathematics - Metric Geometry ,Computer Science - Information Theory ,Mathematics - Probability ,37C10, 94A17, 52A40, 52A20 - Abstract
The Kneser--Poulsen conjecture asserts that the volume of a union of balls in Euclidean space cannot be increased by bringing their centres pairwise closer. We prove that its natural information-theoretic counterpart is true. This follows from a complete answer to a question asked in arXiv:2210.12842 about Gaussian convolutions, namely that the R\'enyi entropy comparisons between a probability measure and its contractive image are preserved when both undergo simultaneous heat flow., Comment: 10 pages. Comments welcome!
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- 2024
42. Benchmarking the integration of hexagonal boron nitride crystals and thin films into graphene-based van der Waals heterostructures
- Author
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Ouaj, Taoufiq, Arnold, Christophe, Azpeitia, Jon, Baltic, Sunaja, Barjon, Julien, Cascales, Jose, Cun, Huanyao, Esteban, David, Garcia-Hernandez, Mar, Garnier, Vincent, Gautam, Subodh K., Greber, Thomas, Hassani, Said Said, Hemmi, Adrian, Jimenéz, Ignacio, Journet, Catherine, Kögerler, Paul, Loiseau, Annick, Maestre, Camille, Metzelaars, Marvin, Schmidt, Philipp, Stampfer, Christoph, Stenger, Ingrid, Steyer, Philippe, Taniguchi, Takashi, Toury, Bérangère, Watanabe, Kenji, and Beschoten, Bernd
- Subjects
Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
We present a benchmarking protocol that combines the characterization of boron nitride (BN) crystals and films with the evaluation of the electronic properties of graphene on these substrates. Our study includes hBN crystals grown under different conditions and scalable BN films deposited by either chemical or physical vapor deposition (CVD or PVD). We explore the complete process from boron nitride growth, over its optical characterization by time-resolved cathodoluminescence (TRCL), to the optical and electronic characterization of graphene by Raman spectroscopy after encapsulation and Hall bar processing. Within our benchmarking protocol we achieve a homogeneous electronic performance within each Hall bar device through a fast and reproducible processing routine. We find that a free exciton lifetime of 1 ns measured on as-grown hBN crystals by TRCL is sufficient to achieve high graphene room temperature charge carrier mobilities of 80,000 cm$^2$/(Vs) at a carrier density of |n| = 10$^{12}$ cm$^{-2}$, while respective exciton lifetimes around 100 ps yield mobilities up to 30,000 cm$^2$/(Vs). For scalable PVD-grown BN films, we measure carrier mobilities exceeding 10,000 cm$^2$/(Vs) which correlates with a graphene Raman 2D peak linewidth of 22 cm$^{-1}$. Our work highlights the importance of the Raman 2D linewidth of graphene as a critical metric that effectively assesses the interface quality (i.e. surface roughness) to the BN substrate, which directly affects the charge carrier mobility of graphene. Graphene 2D linewidth analysis is suitable for all BN substrates and is particularly advantageous when TRCL or BN Raman spectroscopy cannot be applied to specific BN materials such as amorphous or thin films. This underlines the superior role of spatially-resolved spectroscopy in the evaluation of BN crystals and films for the use of high-mobility graphene devices., Comment: 18 pages, 11 figures
- Published
- 2024
43. Spherical Evolution of the Generalized Harmonic Gauge Formulation of General Relativity on Compactified Hyperboloidal Slices
- Author
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Peterson, Christian, Gautam, Shalabh, Vañó-Viñuales, Alex, and Hilditch, David
- Subjects
General Relativity and Quantum Cosmology - Abstract
We report on the successful numerical evolution of the compactified hyperboloidal initial value problem in general relativity using generalized harmonic gauge. We work in spherical symmetry, using a massless scalar field to drive dynamics. Our treatment is based on the dual-foliation approach, proceeding either by using a height function or by solving the eikonal equation to map between frames. Both are tested here with a naive implementation and with hyperboloidal layers. We present a broad suite of numerical evolutions, including pure gauge perturbations, constraint violating and satisfying data with and without scalar field matter. We present calculations of spacetimes with a regular center. For black hole spacetimes we use excision to remove part of the black hole interior. We demonstrate both pointwise and norm convergence at the expected rate of our discretization. We present evolutions in which the scalar field collapses to form a black hole. Evolving nonlinear scalar field perturbations of the Schwarzschild spacetime, we recover the expected quasinormal frequencies and tail decay rates from linear theory., Comment: 21 pages, 10 figures
- Published
- 2024
44. Modelling, Design Optimization and Prototype development of Knee Exoskeleton
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Gautam, Shashank Mani, Singla, Ekta, and Singla, Ashish
- Subjects
Computer Science - Robotics ,Mathematics - Optimization and Control - Abstract
This study focuses on enhancing the design of an existing knee exoskeleton by addressing limitations in the range of motion (ROM) during Sit-to-Stand (STS) motions. While current knee exoskeletons emphasize toughness and rehabilitation, their closed-loop mechanisms hinder optimal ROM, which is crucial for effective rehabilitation. This research aims to optimize the exoskeleton design to achieve the necessary ROM, improving its functionality in rehabilitation. This can be achieved by utilizing kinematic modeling and formulation, the existing design was represented in the non-linear and non-convex mathematical functions. Optimization techniques, considering constraints based on human leg measurements, were applied to determine the best dimensions for the exoskeleton. This resulted in a significant increase in ROM compared to existing models. A MATLAB program was developed to compare the ROM of the optimized exoskeleton with the original design. To validate the practicality of the optimized design, analysis was conducted using a mannequin with average human dimensions, followed by constructing a cardboard dummy model to confirm simulation results. The STS motion of an average human was captured using a camera and TRACKER software, and the motion was compared with that of the dummy model to identify any misalignments between the human and exoskeleton knee joints. Furthermore, a prototype of the knee joint exoskeleton is being developed to further investigate misalignments and improve the design. Future work includes the use of EMG sensors for more detailed analysis and better results.
- Published
- 2024
45. Kvasir-VQA: A Text-Image Pair GI Tract Dataset
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Gautam, Sushant, Storås, Andrea, Midoglu, Cise, Hicks, Steven A., Thambawita, Vajira, Halvorsen, Pål, and Riegler, Michael A.
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Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Artificial Intelligence - Abstract
We introduce Kvasir-VQA, an extended dataset derived from the HyperKvasir and Kvasir-Instrument datasets, augmented with question-and-answer annotations to facilitate advanced machine learning tasks in Gastrointestinal (GI) diagnostics. This dataset comprises 6,500 annotated images spanning various GI tract conditions and surgical instruments, and it supports multiple question types including yes/no, choice, location, and numerical count. The dataset is intended for applications such as image captioning, Visual Question Answering (VQA), text-based generation of synthetic medical images, object detection, and classification. Our experiments demonstrate the dataset's effectiveness in training models for three selected tasks, showcasing significant applications in medical image analysis and diagnostics. We also present evaluation metrics for each task, highlighting the usability and versatility of our dataset. The dataset and supporting artifacts are available at https://datasets.simula.no/kvasir-vqa., Comment: to be published in VLM4Bio 2024, part of the ACM Multimedia (ACM MM) conference 2024
- Published
- 2024
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46. Course Corrections? The Labor Market Returns to Correctional Education Credentials. Working Paper No. 294-0224
- Author
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National Center for Analysis of Longitudinal Data in Education Research (CALDER) at American Institutes for Research (AIR), James Cowan, Dan Goldhaber, and Suvekshya Gautam
- Abstract
Correctional education is a prevalent form of rehabilitation programming for prisoners in the United States. There is limited evidence, however, about the labor market returns to credentials received while incarcerated. Using incarceration, educational, and labor market data in Washington State, we study the labor market returns to GEDs and short-term vocational certificates earned in prison. We identify the returns to credentials by a difference-indifferences design that compares changes in earnings and employment for incarcerated persons who earn a credential to those who enroll in a program but fail to complete a GED or certificate. We estimate that GEDs increase post-incarceration earnings by about $450 per quarter and that vocational certificates increase earnings by about $250 per quarter. Degree completers have higher hourly wages, are more likely to be employed, and work more hours following release. For vocational programs, earnings increases are driven by certificates in construction and manufacturing. [The research presented presented in this report uses confidential data from the Education Research and Data Center (ERDC) located within the Washington Office of Financial Management (OFM).]
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- 2024
47. Perceptions of Political Literacy among Aspiring School Leaders in a Rural Mid-West University Preparation Program
- Author
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Charles L. Lowery, Chetanath Gautam, and Michael E. Hess
- Abstract
This case study investigates aspiring school leaders' perception of political literacy in educational leadership, offering critical recommendations for principal preparation programs, policymakers, and future research. As a qualitative study, the case addresses integrating political literacy policy, developing relevant professional development opportunities, and initiating future research to gauge the possible impact of political literacy as a practice and subject. Moreover, findings reveal the challenges and strategies for implementing political literacy in school settings through the lens of experienced teachers with aspirations to be school leaders. The research suggests that a comprehensive approach emphasizing political literacy may empower aspiring school leaders, improve school-community relations, and promote an informed citizenry. This study signifies a crucial step towards cultivating politically literate school leaders equipped to foster democratic engagement and critical thinking within school communities.
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- 2024
48. When Complexity and Uncertainty Became Life: Delaware School Principals Roles and Leadership Practices during COVID-19 Crisis - A Mixed Method Case Study
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Shelley Rouser, Chetanath Gautam, and Charles L. Lowery
- Abstract
This study explores and explains crisis leadership through surveys and experiential narratives of school principals in the State of Delaware. The study focuses on the lived experiences of school principals for decision-making and responding to the impact that the pandemic (i.e., COVID-19) has had on the educational concerns of students, schools, and communities. The aim is to understand deeply what and how building leaders view their experience leading schools during the crisis, mainly related to COVID-19. Finally, the study aims to contribute to academic literature on improving leadership practice amid the global crisis.
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- 2024
49. A qualitative insight into pre-departure orientation training for aspiring nepalese migrant workers
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Regmi, Pramod, Aryal, Narayan, Van Teijlingen, Edwin, KC, Radheshyam Krishna, Gautam, Manish, and Maharjan, Sanju
- Published
- 2024
50. The Impact of Opioids on Students and Schools in Appalachian and Non-Appalachian Ohio: Educational Leader Perspectives on the Crisis
- Author
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Charles L. Lowery and Chetanath Gautam
- Abstract
Over the last several decades, the opioid crisis has had an increasing impact on the educational environment of schools. The role that principals and superintendents have in leading schools that have been affected by opioids has been mostly overlooked in the research. The present study was conducted in Ohio, a state with areas that have some of the highest death rates due to opioid-related incidents in the nation. Purpose: This study collected data on the perspectives and perceptions of school leaders in Ohio to better understand how principals and superintendents frame their decisions regarding the opioid crisis. Design: We analyze data collected from a survey of 217 Ohio school leaders (n = 164 principals and n = 53 superintendents). The survey required principals and superintendents to rate their perception of the opioid crisis in their schools based on their socioeconomic status, school typology as rural or non-rural, and school location within or outside the Appalachian region. Results: Findings emphasize that opioids remain a factor negatively impacting schools of varying typologies, economic levels, and geographical locations.
- Published
- 2023
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