271,938 results on '"Sarkar A"'
Search Results
2. Hereditary Ectodermal Dysplasia in Two Identical Siblings
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Sarkar A. S., Rao K., and Ajila V.
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anodontia ,consanguineous siblings ,hereditary disease ,hypotrichosis ,hypohidrosis ,Medicine - Abstract
Primary defects in two or more ectodermally-derived tissues during embryonic development characterize ectodermal dysplasia, a vast, varied group of inherited illnesses. Skin, hair, nails, eccrine glands, and teeth are the primary tissues affected. Most cases of ectodermal dysplasia are caused by the X-linked recessive form of the disease (also known as Christ–Siemens–Touraine syndrome), which is passed down from female carriers to their male offspring. It is characterized by an absence of sweat glands (hypohidrosis or anhidrosis), malformed teeth (anodontia or hypodontia), and scant hair (atrichosis or hypotrichosis). Lack of teeth and unusual look were cited as major causes for alarm. The usual manifestations of hypohidrotic hereditary ectodermal dysplasia have been described in two case reports. Two identical siblings with possible typically X-linked recessive hypohidrotic ectodermal dysplasia are described here. Despite the lack of a cure, patients can benefit from a multidisciplinary approach to treatment planning and an expedient diagnosis.
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- 2024
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3. Repurposing Metformin for the Treatment of Atrial Fibrillation: Current Insights
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Sarkar A, Fanous KI, Marei I, Ding H, Ladjimi M, MacDonald R, Hollenberg MD, Anderson TJ, Hill MA, and Triggle CR
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metformin ,atrial fibrillation ,ampk ,hyperglycemia ,hypoglycemia ,cardiac metabolism ,cardio-vascular protection ,atrial remodeling ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Aparajita Sarkar,1 Kareem Imad Fanous,1 Isra Marei,2 Hong Ding,2 Moncef Ladjimi,3 Ross MacDonald,4 Morley D Hollenberg,5 Todd J Anderson,6 Michael A Hill,7 Chris R Triggle2 1Department of Medical Education, Weill Cornell Medicine-Qatar, Doha, Qatar; 2Department of Pharmacology & Medical Education, Weill Cornell Medicine- Qatar, Doha, Qatar; 3Department of Biochemistry & Medical Education, Weill Cornell Medicine-Qatar, Doha, Qatar; 4Health Sciences Library, Weill Cornell Medicine-Qatar, Doha, Qatar; 5Department of Physiology & Pharmacology, and Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; 6Department of Cardiac Sciences and Libin Cardiovascular Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; 7Dalton Cardiovascular Research Center & Department of Medical Pharmacology & Physiology, School of Medicine, University of Missouri, Columbia, Missouri, USACorrespondence: Aparajita Sarkar; Chris R Triggle, Email aps4003@qatar-med.cornell.edu; cht2011@qatar-med.cornell.eduAbstract: Metformin is an orally effective anti-hyperglycemic drug that despite being introduced over 60 years ago is still utilized by an estimated 120 to 150 million people worldwide for the treatment of type 2 diabetes (T2D). Metformin is used off-label for the treatment of polycystic ovary syndrome (PCOS) and for pre-diabetes and weight loss. Metformin is a safe, inexpensive drug with side effects mostly limited to gastrointestinal issues. Prospective clinical data from the United Kingdom Prospective Diabetes Study (UKPDS), completed in 1998, demonstrated that metformin not only has excellent therapeutic efficacy as an anti-diabetes drug but also that good glycemic control reduced the risk of micro- and macro-vascular complications, especially in obese patients and thereby reduced the risk of diabetes-associated cardiovascular disease (CVD). Based on a long history of clinical use and an excellent safety record metformin has been investigated to be repurposed for numerous other diseases including as an anti-aging agent, Alzheimer’s disease and other dementias, cancer, COVID-19 and also atrial fibrillation (AF). AF is the most frequently diagnosed cardiac arrythmia and its prevalence is increasing globally as the population ages. The argument for repurposing metformin for AF is based on a combination of retrospective clinical data and in vivo and in vitro pre-clinical laboratory studies. In this review, we critically evaluate the evidence that metformin has cardioprotective actions and assess whether the clinical and pre-clinical evidence support the use of metformin to reduce the risk and treat AF. Keywords: metformin, atrial fibrillation, AMPK, hyperglycemia, hypoglycemia, cardiac metabolism, cardiovascular protection, atrial remodeling
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- 2024
4. Application of Fuzzy AHP in Priority Based Selection of Financial Indices: A Perspective for Investors
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Jana Subrata, Giri Bibhas Chandra, Sarkar Anirban, Jana Chiranjibe, Stević Željko, and Radovanović Marko
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financial indices ,priority selection ,multi-criteria decision-making (mcdm) ,triangular fuzzy number (tfn) ,fuzzy analytic hierarchy process (f-ahp) ,c44 ,e44 ,m21 ,g17 ,Business ,HF5001-6182 - Abstract
By providing important indicators, financial indices help investors make educated judgements regarding their assets, much like vital sign monitors for the financial markets. The best way for investors to keep up with the market and make strategic adjustments is to keep an eye on these indexes. Researching the most important financial indexes for making educated investing decisions is, thus, quite relevant. Finding the most essential financial indices from an investing standpoint and assigning a weight to each of those indexes are the main goals of this research. A weighted score is derived by combining four financial indices in a Multi-Criteria Decision-Making (MCDM) technique. These objectives are then pursued. Triangular Fuzzy Numbers (TFNs) and the Fuzzy Analytic Hierarchy Process (F-AHP) are used to determine the weights of criteria in this technique. Using these methods together, the research hopes to provide a thorough analysis of the role that different financial indexes have in informing investment choices. This study emphasizes the paramount importance of considering the Price Earning to Growth (PEG) ratio when making investment decisions, followed by the Debt Equity Ratio. Price to Book Value and Dividend Yield, while relevant, carry comparatively less weightage in the overall assessment. Investors are advised to use these insights as a guideline in their financial analysis and decision-making processes.
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- 2024
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5. Impact of dietary and herbal supplements on global health of adult volunteers
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Tomer Abhilasha, Sarkar Amlan Kanti, and Chitme Havagiray R.
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nutritional supplements ,mental health ,multivitamins ,multimineral ,multiherbal ,physical health. ,Medicine - Abstract
The safety and efficacy of multivitamin-multimineral-multiherbal (MVMH) supplementation is in regular debate but should be studied in detail before recommendation. The purpose of the study was to evaluate whether MVMH supplementation affects the physical and mental performance of individuals taking these, as well as to ascertain its safety, doing so through blood, kidney and liver profiles.
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- 2024
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6. The Effect of Human Resource Management and Knowledge Sharing on Employee Performance
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Sarkar Ahmed Saeed, Halwest Jabar Abdullah, and Rawezh Hassib Abdullatif
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human resource management ,knowledge sharing ,employee performance ,teamwork ,training ,development ,Business ,HF5001-6182 - Abstract
This research explores how human resource management (HRM) and knowledge sharing affect employee performance in the Kurdistan Region. The literature review discusses the importance of HRM and Knowledge sharing for organizations and companies and their effects on employee performance. An investigation studied how HRM and knowledge sharing affect employee performance. A questionnaire was used to collect demographic data and assess the correlation between the two factors. The research methodology includes a quantitative approach with a survey of employees working in governmental and non-governmental organizations and companies. A total of 210 responses were collected through the questionnaire. We analyzed data using SPSS software to enhance HRM practices and promote knowledge sharing among employees, which resulted in improved performance. Using SPSS software, data was analyzed to improve HRM practices and encourage knowledge sharing among employees, ultimately leading to better performance.
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- 2023
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7. Global social challenges for development studies in the Crisis in the Anthropocene
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Simon David, Gómez Oscar A., Gasper Des, Bennett Kate, Washbourne Carla-Leanne, Abasli Ilaha, Mukhtarov Farhad, Dias Sonia, and Sarkar Amitabha
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crisis of the anthropocene ,development challenges ,climate change ,human security ,circular economy ,development finance ,planetary health ,Economic growth, development, planning ,HD72-88 ,Social history and conditions. Social problems. Social reform ,HN1-995 - Abstract
This panel discussion session explores some of the central dimensions of the Crisis in the Anthropocene that constitute global social challenges in the context of development studies. The conference theme highlighted the profound human impact on our blue-green-brown planet, that is already breaching planetary boundaries and pushing us beyond the roughly 1.5°C tipping point. This threatens liveability and sustainability in many localities and regions and may well rapidly be ‘off the scale’ of imaginability and survivability. Inevitably, as mounting empirical evidence and increasingly clear projections by the IPCC and other authoritative bodies show, these impacts are unevenly spread, both socially and spatially, both now and over the coming decades. The urgency of appropriate action is undeniable and we already know many dimensions of the required adaptations and transformations. Yet progress mostly remains too slow. These challenges are vital to the development studies community – heterogenous as it is – with our concerns for tackling poverty, inequality, deprivation and environmental degradation globally and locally. Hence this symposium asks what the crisis means for development theory, policy and practice and what development studies can and should be contributing to – and, indeed, whether it is capable of – addressing some key dimensions that warrant greater attention.
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- 2023
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8. Fine structure tuning for strongly correlated functionalities in high entropy oxides
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Wang Di, Sarkar Abhishek, Iankevich Gleb, Zhao Zhibo, Hahn Horst, Kruk Robert, and Kuebel Christian
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high entropy oxide ,stem ,eels ,Microbiology ,QR1-502 ,Physiology ,QP1-981 ,Zoology ,QL1-991 - Published
- 2024
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9. Copper(ii) complexes supported by modified azo-based ligands: Nucleic acid binding and molecular docking studies
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Tripathi Mamta, Asatkar Ashish Kumar, Antony Stalin, Dash Mrinal Kanti, Roymahapatra Gourisankar, Pande Rama, Sarkar Avijit, Aldakheel Fahad M., Binshaya Abdulkarim S., Alharthi Nahed S., Alaofi Ahmed L., Alqahtani Mohammed S., and Syed Rabbani
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azo ,copper(ii) complexes ,dft ,ct-dna ,t-rna ,molecular docking ,Chemistry ,QD1-999 - Abstract
Two new copper(ii) complexes [CuL1] (1) and [CuL2] (2) derived from azo-based ligands 2-hydroxy-5-p-tolylazo-benzaldehyde (HL1) and 1-(2-hydroxy-5-p-tolylazo-phenyl)-ethan-one (HL2) were synthesized. These two ligands and their metal complexes were characterized by elemental analysis, nuclear magnetic resonance (1H and 13C), infrared, and UV/Vis spectroscopic techniques. Spectroscopy and other theoretical studies reveal the geometry of copper complexes, and their binding affinity towards nucleic acids are major groove binding.
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- 2022
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10. Transthyretin and Receptor for Advanced Glycation End Product’s Differential Levels Associated with the Pathogenesis of Rheumatoid Arthritis
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Monu, Agnihotri P, Saquib M, Sarkar A, Chakraborty D, Kumar U, and Biswas S
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rheumatoid arthritis (ra) ,differential proteins (dps) ,post-translational modifications (ptm) ,transthyretin (ttr) ,advanced glycation end products (ages) ,receptors for advanced glycation end products (rage). ,Pathology ,RB1-214 ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Monu,1,2 Prachi Agnihotri,1 Mohd Saquib,1,2 Ashish Sarkar,1,2 Debolina Chakraborty,1,2 Uma Kumar,3 Sagarika Biswas1 1Council of Scientific and Industrial Research -Institute of Genomics & Integrative Biology (CSIR–IGIB), Delhi, 110007, India; 2Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India; 3All India Institute of Medical Sciences, New Delhi, 110029, IndiaCorrespondence: Sagarika BiswasIntegrative and Functional Biology Department CSIR- Institute of Genomics & Integrative Biology, Mall Road, Delhi, 110 007, IndiaTel +91 11 27667602Fax +91-11-27667471; +9818004740Email sagarika.biswas@igib.res.inObjective: Rheumatoid arthritis (RA) is a chronic autoimmune, inflammatory joint disease. The identification of multifaceted etiological changes at the protein level in RA remains an important need. We aimed to identify differential proteins (DPs) and gene profiles to uncover inflammatory indicators and their association to RA pathogenesis.Methods: 2-DE and SWATH-MS were used to identify DPs in RA and healthy control plasma. Fluorescence phenylboronate gel electrophoresis (Flu-PAGE) with mass spectrometry was used for protein glycation in RA plasma. Disease specificity of identified DPs was confirmed by ELISA and Western blot analysis. The gene expressions of selected DPs were evaluated by qRT-PCR in PBMCs of RA, systemic lupus erythematosus (SLE), spondyloarthritis (SpA), and osteoarthritis (OA). The functional implication of glycated protein was determined by in- silico and validated by in vitro analysis in fibroblast-like synoviocytes.Results: A total of 150 DPs (127 increased and 23 decreased) were identified by 2-DE and SWATH-MS analysis in RA plasma compared to healthy control (HC). Nine proteins were identified as glycated by Flu-PAGE LC-MS/MS. Transthyretin (TTR), serotransferrin, and apolipoprotein-A1 (Apo-A1) were found to be differential and glycated. ELISA and Western blot results revealed the disease-specific increased expression of TTR and RAGE in RA. The qRT-PCR results signify the aberrant gene expression of TTR and RAGE, found to be associated with RA when compared with SLE, SpA, and OA PBMCs. TTR-RAGE interactions were predicted by in-silico and validated by in-vitro analysis using RA-FLS. The increased levels of pro-inflammatory cytokines IL-6, IL-1β, TNF-α, and differently expressed TTR and RAGE were confirmed in fibroblast-like synoviocytes under inflammatory conditions.Conclusion: Our findings showed that the level of TTR was increased in RA plasma, along with an altered glycation rate. TTR and RAGE aberrant gene expression in PBMCs are the key events associated with RA, and TNF-α activates the NF-KB pathways and promote TTR and RAGE differential expressions that may have pathogenic/inflammatory significance.Keywords: rheumatoid arthritis, differential proteins, post-translational modifications, transthyretin, advanced glycation end products, receptor for advanced glycation end products
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- 2021
11. Aspects of the chiral crossover transition in (2+1)-flavor QCD with M\'{o}bius domain-wall fermions
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Gavai, Rajiv V., Jaensch, Mischa E., Kaczmarek, Olaf, Karsch, Frithjof, Sarkar, Mugdha, Shanker, Ravi, Sharma, Sayantan, Sharma, Sipaz, and Ueding, Tristan
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High Energy Physics - Lattice ,High Energy Physics - Phenomenology - Abstract
The non-singlet part of the chiral symmetry in QCD with two light flavors is known to be restored through a crossover transition at a pseudo-critical temperature. However, the temperature dependence of the singlet part of the chiral symmetry and whether it is effectively restored at the same temperature is not well understood. Using (2+1)-flavor QCD configurations generated using the M\"{o}bius domain-wall discretization on an $N_\tau=8$ lattice, we construct suitable observables where the singlet and non-singlet chiral symmetries are disentangled in order to study their temperature dependence across the crossover transition. From the peak of the disconnected part of the chiral susceptibility, we obtain a pseudo-critical temperature $T_{pc}=158.7{}_{{}-2.3}^{{}+2.6}$ MeV where the non-singlet part of the chiral symmetry is effectively restored. From a calculation of the topological susceptibility and its temperature dependence we find that the singlet $U_A(1)$ part of the chiral symmetry is not effectively restored at $T<186$ MeV., Comment: Number of pages: 10; Number of figures: 6
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- 2024
12. Islands for black holes in a hybrid quantum state
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Potaux, Yohan, Sarkar, Debajyoti, and Solodukhin, Sergey N.
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High Energy Physics - Theory ,General Relativity and Quantum Cosmology - Abstract
Following our previous work on hybrid quantum states in the RST model, we study its most interesting solution representing a completely regular spacetime with the structure of causal diamond, containing an apparent horizon and radiation at infinity. Adapting recent computations of radiation entropy in terms of the entropy of entanglement, we find that this entropy follows a Page curve. This confirms our previous result [1], which was obtained by directly calculating the thermodynamic entropy of radiation at infinity. We also investigate the presence of a possible island in these systems, and find that it does not seem to play a role in contributing to the generalized black hole entropy.
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- 2024
13. Phase transitions in the presence of fluctuating charge-density wave in two-dimensional film of kagome metals
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Wildeboer, Julia, Sarkar, Saheli, and Tsvelik, Alexei M.
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Condensed Matter - Strongly Correlated Electrons - Abstract
We determine the nature of a phase transition in a model describing an interaction of multiple charge density waves in a two dimensional film. The model was introduced by two of the authors in Phys. Rev. B {\bf 108}, 045119 (2023) to describe fluctuations in charge density wave order in the kagome metals AV$_3$Sb$_5$ (A=K, Rb, Cs) in two dimensions. The situation is nontrivial since the transition occurs in the region of phase diagram where the unbound vortices compete with the interaction between charge density waves. Here, we study the nature of the phase transition via Metropolis Monte Carlo simulations. The 3-component order parameter, the susceptibility, the energy per site, and the specific heat are measured for a range of temperatures for different lattice sizes $L=8,16,24,32$. The finite size scaling analysis indicates the presence of a second-order transition., Comment: 9 pages, 9 figures
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- 2024
14. Verbosity $\neq$ Veracity: Demystify Verbosity Compensation Behavior of Large Language Models
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Zhang, Yusen, Das, Sarkar Snigdha Sarathi, and Zhang, Rui
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Computer Science - Computation and Language - Abstract
When unsure about an answer, humans often respond with more words than necessary, hoping that part of the response will be correct. We observe a similar behavior in large language models (LLMs), which we term "Verbosity Compensation" (VC). VC is harmful because it confuses the user understanding, leading to low efficiency, and influences the LLM services by increasing the latency and cost of generating useless tokens. In this paper, we present the first work that defines and analyzes Verbosity Compensation, explores its causes, and proposes a simple mitigating approach. We define Verbosity Compensation as the behavior of generating responses that can be compressed without information loss when prompted to write concisely. Our experiments, conducted on five datasets of knowledge and reasoning-based QA tasks with 14 newly developed LLMs, reveal three conclusions. 1) We reveal a pervasive presence of verbosity compensation across all models and all datasets. Notably, GPT-4 exhibits a VC frequency of 50.40%. 2) We reveal the large performance gap between verbose and concise responses, with a notable difference of 27.61% on the Qasper dataset. We also demonstrate that this difference does not naturally diminish as LLM capability increases. Both 1) and 2) highlight the urgent need to mitigate the frequency of VC behavior and disentangle verbosity with veracity. We propose a simple yet effective cascade algorithm that replaces the verbose responses with the other model-generated responses. The results show that our approach effectively alleviates the VC of the Mistral model from 63.81% to 16.16% on the Qasper dataset. 3) We also find that verbose responses exhibit higher uncertainty across all five datasets, suggesting a strong connection between verbosity and model uncertainty. Our dataset and code are available at https://github.com/psunlpgroup/VerbosityLLM., Comment: 19 pages, 6 figures
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- 2024
15. Monte Carlo Simulation of Anisotropic Ising Model Using Metropolis and Wolff Algorithm
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Iqbal, Basit and Sarkar, Kingshuk
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Condensed Matter - Statistical Mechanics ,Condensed Matter - Materials Science - Abstract
We employ Monte Carlo techniques, utilizing the Metropolis and Wolff algorithms, to investigate phase behavior and phase transitions in anisotropic Ising models. Our study encompasses the thermodynamic properties, evaluating energy, magnetization, specific heat, magnetic susceptibility, magnetic entropy, and the Binder cumulant. Additionally, we examine the impact of external fields on these thermodynamic quantities at different externally applied field values. We accurately determine the critical temperature for various model scenarios by analyzing the Binder cumulant. Our investigations also include an analysis of the hysteresis loop for the model for different an-isotropic cases. In particular, our study presents the magnetocaloric effect, which is the change in temperature of magnetic material when exposed to a changing magnetic field, in the different anisotropic cases of the Ising model., Comment: 16 pages, 9 figures
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- 2024
16. EO-GRAPE and EO-DRLPE: Open and Closed Loop Approaches for Energy Efficient Quantum Optimal Control
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Fauquenot, Sebastiaan, Sarkar, Aritra, and Feld, Sebastian
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Quantum Physics ,Computer Science - Emerging Technologies ,Electrical Engineering and Systems Science - Systems and Control - Abstract
This research investigates the possibility of using quantum optimal control techniques to co-optimize the energetic cost and the process fidelity of a quantum unitary gate. The energetic cost is theoretically defined, and thereby, the gradient of the energetic cost for pulse engineering is derived. We empirically demonstrate the Pareto optimality in the trade-off between process fidelity and energetic cost. Thereafter, two novel numerical quantum optimal control approaches are proposed: (i) energy-optimized gradient ascent pulse engineering (EO-GRAPE) as an open-loop gradient-based method, and (ii) energy-optimized deep reinforcement learning for pulse engineering (EO-DRLPE) as a closed-loop method. The performance of both methods is probed in the presence of increasing noise. We find that the EO-GRAPE method performs better than the EO-DRLPE methods with and without a warm start for most experimental settings. Additionally, for one qubit unitary gate, we illustrate the correlation between the Bloch sphere path length and the energetic cost., Comment: 19 pages, 11 figures
- Published
- 2024
17. On a t-stuffle product formula for interpolated multiple zeta values
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Sarkar, Pitu and Tamang, Nita
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Mathematics - Number Theory ,11M32 - Abstract
In this paper, we obtain a restricted decomposition formula for interpolated multiple zeta values using t-stuffle product. We then derive a recursive formula of t-stuffle product, which also provides a route to the same formula. In both cases, combinatorial description of t-stuffle product is our basic tool. We also provide alternative proofs by mathematical induction for some of the results., Comment: 22 Pages
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- 2024
18. Machine learning for prediction of dose-volume histograms of organs-at-risk in prostate cancer from simple structure volume parameters
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Saha, Saheli, Banerjee, Debasmita, Ram, Rishi, Reddy, Gowtham, Guha, Debashree, Sarkar, Arnab, Dutta, Bapi, S, Moses ArunSingh, Chakraborty, Suman, and Mallick, Indranil
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Computer Science - Machine Learning - Abstract
Dose prediction is an area of ongoing research that facilitates radiotherapy planning. Most commercial models utilise imaging data and intense computing resources. This study aimed to predict the dose-volume of rectum and bladder from volumes of target, at-risk structure organs and their overlap regions using machine learning. Dose-volume information of 94 patients with prostate cancer planned for 6000cGy in 20 fractions was exported from the treatment planning system as text files and mined to create a training dataset. Several statistical modelling, machine learning methods, and a new fuzzy rule-based prediction (FRBP) model were explored and validated on an independent dataset of 39 patients. The median absolute error was 2.0%-3.7% for bladder and 1.7-2.4% for rectum in the 4000-6420cGy range. For 5300cGy, 5600cGy and 6000cGy, the median difference was less than 2.5% for rectum and 3.8% for bladder. The FRBP model produced errors of 1.2%, 1.3%, 0.9% and 1.6%, 1.2%, 0.1% for the rectum and bladder respectively at these dose levels. These findings indicate feasibility of obtaining accurate predictions of the clinically important dose-volume parameters for rectum and bladder using just the volumes of these structures.
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- 2024
19. SciDQA: A Deep Reading Comprehension Dataset over Scientific Papers
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Singh, Shruti, Sarkar, Nandan, and Cohan, Arman
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Computer Science - Computation and Language - Abstract
Scientific literature is typically dense, requiring significant background knowledge and deep comprehension for effective engagement. We introduce SciDQA, a new dataset for reading comprehension that challenges LLMs for a deep understanding of scientific articles, consisting of 2,937 QA pairs. Unlike other scientific QA datasets, SciDQA sources questions from peer reviews by domain experts and answers by paper authors, ensuring a thorough examination of the literature. We enhance the dataset's quality through a process that carefully filters out lower quality questions, decontextualizes the content, tracks the source document across different versions, and incorporates a bibliography for multi-document question-answering. Questions in SciDQA necessitate reasoning across figures, tables, equations, appendices, and supplementary materials, and require multi-document reasoning. We evaluate several open-source and proprietary LLMs across various configurations to explore their capabilities in generating relevant and factual responses. Our comprehensive evaluation, based on metrics for surface-level similarity and LLM judgements, highlights notable performance discrepancies. SciDQA represents a rigorously curated, naturally derived scientific QA dataset, designed to facilitate research on complex scientific text understanding., Comment: 18 pages, Accepted to EMNLP 2024
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- 2024
20. Probing the origin of the extended flaring branch of Z-type X-ray binaries GX 340+0 and GX 5-1 using AstroSat
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Dutta, Tanmoy, Pahari, Mayukh, Sarkar, Anish, Bhattacharyya, Sudip, and Bhargava, Yash
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
`Z' type neutron star low-mass X-ray binaries typically show a `Z'-like three-branched track in their hardness intensity diagram. However, a few such `Z' sources show an additional branch known as the extended flaring branch (EFB). EFB has been poorly studied, and its origin is not known. It is thought to be an extension of the flaring branch (FB) or associated with Fe K$\alpha$ complex or an additional continuum due to the radiative recombination continuum (RRC) process. Using AstroSat observations, we have detected the EFB from two `Z' sources, GX 340+0 and GX 5-1, and performed a broadband spectral analysis in the 0.5-22 keV energy range. During EFB, both sources show the presence of a significant RRC component with absorption edges at $7.91^{+0.16}_{-0.15}$ keV and $8.10^{+0.16}_{-0.17}$ keV, respectively along with blackbody radiation and thermal Comptonisation. No signature of RRC was detected during the FB, which is adjoint to the EFB. No Fe K$\alpha$ complex is detected. Interestingly, inside EFB dips of GX 5-1, for the first time, we have detected flaring events of 30-60s, which can be modelled with a single blackbody radiation. During the FB to EFB transition, an increase in the blackbody radius by a factor of 1.5-2 is observed in both sources. Our analysis strongly suggests that EFB is not an extension of FB or caused by the Fe K$\alpha$ complex. Rather, it is caused by a sudden expansion of the hot, thermalised boundary layer and subsequent rapid cooling., Comment: 14 pages, 10 figures, 6 tables, Accepted for publication in MNRAS
- Published
- 2024
21. Findings of the IWSLT 2024 Evaluation Campaign
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Ahmad, Ibrahim Said, Anastasopoulos, Antonios, Bojar, Ondřej, Borg, Claudia, Carpuat, Marine, Cattoni, Roldano, Cettolo, Mauro, Chen, William, Dong, Qianqian, Federico, Marcello, Haddow, Barry, Javorský, Dávid, Krubiński, Mateusz, Lam, Tsz Kin, Ma, Xutai, Mathur, Prashant, Matusov, Evgeny, Maurya, Chandresh, McCrae, John, Murray, Kenton, Nakamura, Satoshi, Negri, Matteo, Niehues, Jan, Niu, Xing, Ojha, Atul Kr., Ortega, John, Papi, Sara, Polák, Peter, Pospíšil, Adam, Pecina, Pavel, Salesky, Elizabeth, Sethiya, Nivedita, Sarkar, Balaram, Shi, Jiatong, Sikasote, Claytone, Sperber, Matthias, Stüker, Sebastian, Sudoh, Katsuhito, Thompson, Brian, Turchi, Marco, Waibel, Alex, Watanabe, Shinji, Wilken, Patrick, Zemánek, Petr, and Zevallos, Rodolfo
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Computer Science - Computation and Language - Abstract
This paper reports on the shared tasks organized by the 21st IWSLT Conference. The shared tasks address 7 scientific challenges in spoken language translation: simultaneous and offline translation, automatic subtitling and dubbing, speech-to-speech translation, dialect and low-resource speech translation, and Indic languages. The shared tasks attracted 18 teams whose submissions are documented in 26 system papers. The growing interest towards spoken language translation is also witnessed by the constantly increasing number of shared task organizers and contributors to the overview paper, almost evenly distributed across industry and academia., Comment: IWSLT 2024; 59 pages
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- 2024
22. Multiplicities of weakly graded families of ideals
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Sarkar, Parangama
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Mathematics - Commutative Algebra - Abstract
We extend the notion of multiplicity for weakly graded families of ideals. We prove the ``volume=multiplicity" formula and Minkowski inequality for weakly graded families of ideals. For weakly graded families of ideals of the form $\{(I_n:K)\}$ where $\{I_n\}$ is a graded family, we relate this multiplicity with multiplicity of $\{I_n\}$ and provide a necessary and sufficient condition for the equality in Minkowski inequality if $\{I_n\}$ is a bounded filtration. We generalize a result of Rees characterizing the inclusion of ideals with the same multiplicity for weakly graded families of ideals $\{(I_n:K)\}$. We also explore the asymptotic behaviour of $\ell_R(H_{\mathfrak m}^0(R/(I_n:K)))$., Comment: 15 pages, Comments are welcome
- Published
- 2024
23. Carroll in Shallow Water
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Bagchi, Arjun, Banerjee, Aritra, Mondal, Saikat, and Sarkar, Sayantan
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High Energy Physics - Theory ,Physics - Fluid Dynamics - Abstract
We discover a surprising connection between Carrollian symmetries and hydrodynamics in the shallow water approximation. Carrollian symmetries arise in the speed of light going to zero limit of relativistic Poincar\'e symmetries. Using a recent gauge theoretic description of shallow water wave equations we find that the actions corresponding to two different waves, viz. the so called flat band solution and the Poincar\'e waves map exactly to the actions of the electric and magnetic sectors of Carrollian electrodynamics., Comment: 7 pages including a supplement, 3 figures. Comments welcome!
- Published
- 2024
24. X-ray and optical analysis of the distant, merging double cluster SPT-CLJ2228-5828, its gas bridge, and shock front
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Migkas, K., Sommer, M. W., Schrabback, T., Carrasco, E. R., Zenteno, A., Zohren, H., Bleem, L. E., Nazaretyan, V., Bayliss, M., Bulbul, E., Floyd, B., Gassis, R., McDonald, M., Grandis, S., Reichardt, C., Sarkar, A., Sharon, K., and Somboonpanyakul, T.
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Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Galaxy cluster mergers are excellent laboratories for studying a wide variety of different physical phenomena. Such a unique system is the distant SPT-CLJ2228-5828 cluster merger located at $z\approx 0.77$. Previous analyses via Sunyaev-Zeldovich and weak lensing data suggested that the system potentially was a dissociative cluster post-merger. In this work, we use new, deep XMM-Newton data to study the hot gas in X-rays, spectroscopic Gemini data to precisely determine the redshift of the two mass concentrations, and new HST data to improve the total mass estimates of the two components. We find that SPT-CLJ2228-5828 constitutes a pre-merging, double cluster system, instead of a post-merger. The merging process of the two clusters has started with their outskirt gas colliding with a $\sim 22^{\circ}-27^{\circ}$ on the plane of the sky. We fully characterize the surface brightness, gas density, temperature, pressure, and entropy profiles of the two merging clusters. The two systems have very similar X-ray properties with a moderate cluster mass of $M_{\text{tot}}\sim (2.1-2.4)\times 10^{14}\ M_{\odot}$. A $\approx 333$ kpc long gas bridge connecting the two clusters is detected at a $5.8\sigma$ level. The baryon overdensity of the excess bridge gas is $\delta_{\text{b}}\sim (75-320)$ across the length of the bridge and its gas mass is $M_{\text{gas}}\sim 1.4\times 10^{12}\ M_{\odot}$. Gas density and temperature jumps are also found across the gas bridge, revealing the existence of a weak shock front with a Mach number $\mathcal{M}\sim 1.1$. The gas pressure and entropy are also increased at the position of the shock front. We estimate the age of the shock front to be $\lesssim 100$ Myr and its kinetic energy $\sim 2.4\times 10^{44}$ erg s$^{-1}$. SPT-CLJ2228-5828 is the first such high-$z$ pre-merger with a gas bridge and a shock front to be studied in X-rays., Comment: 21 pages, 9 figures. Submitted for publication in A&A
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- 2024
25. Scar-induced imbalance in staggered Rydberg ladders
- Author
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Pal, Mainak, Sarkar, Madhumita, Sengupta, K., and Sen, Arnab
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Quantum Physics ,Condensed Matter - Strongly Correlated Electrons - Abstract
We demonstrate that the kinematically-constrained model of Rydberg atoms on a two-leg ladder with staggered detuning, $\Delta \in [0,1]$, has quantum many-body scars (QMBS) in its spectrum and represents a non-perturbative generalization of the paradigmatic PXP model defined on a chain. We show that these QMBS result in coherent many-body revivals and site-dependent magnetization dynamics for both N\'eel and Rydberg vacuum initial states around $\Delta=1$. The latter feature leads to eigenstate thermalization hypothesis (ETH)-violating finite imbalance at long times in a disorder free system. This is further demonstrated by constructing appropriate local imbalance operators that display finite long-time averages for N\'eel and vacuum initial states. We also study the fidelity and Shannon entropy for such dynamics which, along with the presence of long-time finite imbalance, brings out the qualitatively different nature of QMBS in PXP ladders with $\Delta \sim 1$ from those in the PXP chain., Comment: v1; 4+$\epsilon$ pages; 3 figs; Supplementary Materials attached
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- 2024
26. Noisy Stark probes as quantum-enhanced sensors
- Author
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Sarkar, Saubhik and Bayat, Abolfazl
- Subjects
Quantum Physics - Abstract
Wannier-Stark localization has been proven to be a resource for quantum-enhanced sensitivity with super-Heisenberg scaling. An extremely promising feature of such probes are their ability to showcase such enhanced scaling even dynamically with system size, on top of the quadratic scaling in time. In this work, we address the issue of decoherence that occurs during evolution and characterize how that affects the sensing performance. We determine the parameter domains in which the enhancement is sustained under dephasing dynamics. As the open system dynamics is closely connected to evolution under an effective non-Hermitian Hamiltonian, we consider two such scenarios that can be engineered in an experiment. The first one is a trace-preserving dynamical description and shows the existence of quantum-enhanced sensitivity. The second one considers a non-Hermitian lattice where the presence of super-Heisenberg sensitivity further proves that quantum advantages of the Stark probes indeed can be sustained during noisy dynamics., Comment: 4.5 pages, 3 figures. Comments are welcome
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- 2024
27. AI Should Challenge, Not Obey
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Sarkar, Advait
- Subjects
Computer Science - Human-Computer Interaction - Abstract
Let's transform our robot secretaries into Socratic gadflies., Comment: Advait Sarkar. 2024. AI Should Challenge, Not Obey. Commun. ACM 67, 10 (October 2024), 18-21. https://doi.org/10.1145/3649404
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- 2024
- Full Text
- View/download PDF
28. J-contractive operator valued functions, vector valued de Branges spaces and functional models
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Garg, Bharti and Sarkar, Santanu
- Subjects
Mathematics - Functional Analysis - Abstract
In this paper, we study the reproducing kernel Hilbert spaces (RKHS) which are constructed from \( J \)-contractive operator valued analytic functions on the upper half plane. First, we discuss the Potapov-Ginzburg transform of a specific class of Fredholm operators, investigate some of its properties, and outline sufficient conditions for a \( J \)-contractive operator to be \( J \)-bicontractive. Subsequently, we construct certain classes of vector valued de Branges spaces and aim to explore the significance of these classes. Using these spaces, we present a functional model for simple Volterra operator nodes. Additionally, we analyze their connections with another classes of de Branges spaces which are based on a pair of Fredholm operator valued analytic functions. Finally, we discuss a functional model for simple, closed, densely defined, symmetric operators with infinite deficiency indices within this framework., Comment: 43 pages
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- 2024
29. Products of two orthogonal projections
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Bhattacharjee, Jaydeep and Sarkar, Jaydeb
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Mathematics - Functional Analysis ,Mathematics - Complex Variables ,Mathematics - Operator Algebras ,47A68, 15A23, 30J05, 46E25, 32A35 - Abstract
We study operators that are products of two orthogonal projections. Our results complement some of the classical results of Crimmins and von Neumann. Particular emphasis has been given to projections associated with inner functions defined on the polydisc., Comment: 21 pages
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- 2024
30. Very High-energy Gamma-Ray Episodic Activity of Radio Galaxy NGC 1275 in 2022-2023 Measured with MACE
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Godambe, S., Mankuzhiyil, N., Borwankar, C., Ghosal, B., Tolamatti, A., Pal, M., Chandra, P., Khurana, M., Pandey, P., Dar, Z. A., Godiyal, S., Hariharan, J., Anand, Keshav, Norlha, S., Sarkar, D., Thubstan, R., Venugopal, K., Pathania, A., Kotwal, S., Kumar, Raj, Bhatt, N., Chanchalani, K., Das, M., Singh, K. K., Gour, K. K., Kothari, M., Kumar, Nandan, Kumar, Naveen, Marandi, P., Kushwaha, C. P., Koul, M. K., Dorjey, P., Dorji, N., Chitnis, V. R., Rannot, R. C., Bhattacharyya, S., Chouhan, N., Dhar, V. K., Sharma, M., and Yadav, K. K.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
The radio galaxy NGC 1275, located at the central region of Perseus cluster, is a well-known very high-energy (VHE) gamma-ray emitter. The Major Atmospheric Cherenkov Experiment Telescope has detected two distinct episodes of VHE (E > 80 GeV) gamma-ray emission from NGC 1275 during 2022 December and 2023 January. The second outburst, observed on 2023 January 10, was the more intense of the two, with flux reaching 58$\%$ of the Crab Nebula flux above 80 GeV. The differential energy spectrum measured between 80 GeV and 1.5 TeV can be described by a power law with a spectral index of $\Gamma = - 2.90 \pm 0.16_{stat}$ for both flaring events. The broadband spectral energy distribution derived from these flares, along with quasisimultaneous low-energy counterparts, suggests that the observed gamma-ray emission can be explained using a homogeneous single-zone synchrotron self-Compton model. The physical parameters derived from this model for both flaring states are similar. The intermediate state observed between two flaring episodes is explained by a lower Doppler factor or magnetic field, which subsequently returned to its previous value during the high-activity state observed on 2023 January 10., Comment: 7 Pages, 5 Figures, and 1 Table
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- 2024
- Full Text
- View/download PDF
31. Advancements in Data Processing and Calibration for the Hyperspectral Imaging Satellite (HySIS)
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Garg, Ankur, Patil, Abhishek, Sarkar, Meenakshi, Moorthi, S. Manthira, and Dhar, Debajyoti
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Electrical Engineering and Systems Science - Image and Video Processing - Abstract
Hyperspectral imaging is a powerful tool for Earth exploration, allowing for detailed analysis of spectral features. India has launched a dedicated hyperspectral Earth observation satellite capable of capturing data across a wide electromagnetic spectrum from 400 nm to 2500 nm, with an impressive spatial resolution of 30 meters. This paper details the comprehensive calibration procedures performed before launch to ensure data accuracy and instrument optimization for Hysis payload. Performance metrics demonstrate the satellite's ability to deliver high-quality imagery of the Earth's surface. In-orbit radiometric and geometric calibration further validated the satellite's functionality, while observations and anomalies encountered during this phase led to the development of specialized algorithms for operational enhancement. The paper outlines the operational data processing pipeline, covering stages from raw data acquisition to final image generation. A thorough assessment of the satellite's radiometric and geometric quality reinforces its reliability and effectiveness, highlighting its contribution to advancing Earth exploration through hyperspectral imaging technology., Comment: Preprint
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- 2024
32. Quantum-enhanced sensing of spin-orbit coupling without fine-tuning
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Yi, Bin, Bayat, Abolfazl, and Sarkar, Saubhik
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Quantum Physics - Abstract
Spin-orbit coupling plays an important role in both fundamental physics and technological applications. Precise estimation of the spin-orbit coupling is necessary for accurate designing across various physical setups such as solid state devices and quantum hardware. Here, we exploit quantum features in a 1D quantum wire for estimating the Rashba spin-orbit coupling with enhanced sensitivity beyond the capability of classical probes. The Heisenberg limited enhanced precision is achieved across a wide range of parameters and does not require fine tuning. Such advantage is directly related to the gap-closing nature of the probe across the entire relevant range of parameters. This provides clear advantage over conventional criticality-based quantum sensors in which quantum enhanced sensitivity can only be achieved through fine-tuning around the phase transition point. We have demonstrated quantum enhanced sensitivity for both single particle and interacting many-body probes. In addition to extending our results to thermal states and the multi-parameter scenario, we have provided an measurement basis to perform close to the ultimate precision., Comment: 6 pages, 5 figures. Comments are welcome
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- 2024
33. Unraveling the Origin of Mysterious Luminescence peak at 3.45 eV in GaN Nanowires
- Author
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Bhunia, Swagata, Chatterjee, Soumyadip, Sarkar, Ritam, Nag, Dhiman, Mahapatra, Suddhasatta, and Laha, Apurba
- Subjects
Physics - Applied Physics - Abstract
The demand for GaN Nanowires (NWs)-based optoelectronic devices has rapidly increased over the past few years due to its superior crystalline quality compare to their planar counterparts. However, NWs-based devices face significant challenges because of number of surface states, basal plane stacking faults and coalescence related defect states. While the origins of most of the defect states have been identified and mitigated using well-established methods, the origins of few defect states remain unknown, and thus their suppression methods have yet to be explored. One such defect state is the 3.45 eV luminescence peak, known as the UX-band. In this report, we have investigated the origin of this peak in NWs grown on a sapphire substrate by using Plasma Assisted Molecular Beam Epitaxy (PAMBE) tool. We have found that the defect states, generated due to oxygen incorporation, especially when the oxygen atoms substitute the Ga atoms, are the primary cause of this band. Actually the excitons are localized at this defect center and the radiative recombination of localized excitons gives the characteristic UX-band. By protecting the NWs from oxygen incorporation through AlN encapsulation process, we have completely suppressed the 3.45 eV peak and proved further that the peak is caused by oxygen induced defect states. Thus we have addressed an issue that persisted over the last three decades, potentially paving the way for efficiency improvements in optoelectronic devices.
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- 2024
34. LEGO_HQEC: A Software Tool for Analyzing Holographic Quantum Codes
- Author
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Fan, Junyu, Steinberg, Matthew, Jahn, Alexander, Cao, Chunjun, Sarkar, Aritra, and Feld, Sebastian
- Subjects
Quantum Physics - Abstract
Quantum error correction (QEC) is a crucial prerequisite for future large-scale quantum computation. Finding and analyzing new QEC codes, along with efficient decoding and fault-tolerance protocols, is central to this effort. Holographic codes are a recent class of QEC subsystem codes derived from holographic bulk/boundary dualities. In addition to exploring the physics of such dualities, these codes possess useful QEC properties such as tunable encoding rates, distance scaling competitive with topological codes, and excellent recovery thresholds. To allow for a comprehensive analysis of holographic code constructions, we introduce LEGO_HQEC, a software package utilizing the quantum LEGO formalism. This package constructs holographic codes on regular hyperbolic tilings and generates their stabilizer generators and logical operators for a specified number of seed codes and layers. Three decoders are included: an erasure decoder based on Gaussian elimination; an integer-optimization decoder; and a tensor-network decoder. With these tools, LEGO_HQEC thus enables future systematic studies regarding the utility of holographic codes for practical quantum computing.
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- 2024
35. MassiveGNN: Efficient Training via Prefetching for Massively Connected Distributed Graphs
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Sarkar, Aishwarya, Ghosh, Sayan, Tallent, Nathan R., and Jannesari, Ali
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Computer Science - Distributed, Parallel, and Cluster Computing ,Computer Science - Machine Learning ,Computer Science - Performance - Abstract
Graph Neural Networks (GNN) are indispensable in learning from graph-structured data, yet their rising computational costs, especially on massively connected graphs, pose significant challenges in terms of execution performance. To tackle this, distributed-memory solutions such as partitioning the graph to concurrently train multiple replicas of GNNs are in practice. However, approaches requiring a partitioned graph usually suffer from communication overhead and load imbalance, even under optimal partitioning and communication strategies due to irregularities in the neighborhood minibatch sampling. This paper proposes practical trade-offs for improving the sampling and communication overheads for representation learning on distributed graphs (using popular GraphSAGE architecture) by developing a parameterized continuous prefetch and eviction scheme on top of the state-of-the-art Amazon DistDGL distributed GNN framework, demonstrating about 15-40% improvement in end-to-end training performance on the National Energy Research Scientific Computing Center's (NERSC) Perlmutter supercomputer for various OGB datasets., Comment: In Proc. of the IEEE International Conference on Cluster Computing (CLUSTER), 2024
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- 2024
36. Enhancing Image Resolution: A Simulation Study and Sensitivity Analysis of System Parameters for Resourcesat-3S/3SA
- Author
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Garg, Ankur, Sarkar, Meenakshi, Moorthi, S. M., and Dhar, Debajyoti
- Subjects
Electrical Engineering and Systems Science - Image and Video Processing - Abstract
Resourcesat-3S/3SA, an upcoming Indian satellite, is designed with Aft and Fore payloads capturing stereo images at look angles of -5deg and 26deg, respectively. Operating at 632.6 km altitude, it features a panchromatic (PAN) band offering a Ground Sampling Distance (GSD) of 1.25 meters and a 60 km swath. To balance swath width and resolution, an Instantaneous Geometric Field of View (IGFOV) of 2.5 meters is maintained while ensuring a 1.25-meter GSD both along and across track. Along-track sampling is achieved through precise timing, while across-track accuracy is ensured by using two staggered pixel arrays. Signal-to-Noise Ratio (SNR) is enhanced through Time Delay and Integration (TDI), employing two five-stage subarrays spaced 80 {\mu}m apart along the track, with a 4 {\mu}m (0.5 pixel) stagger in the across-track direction to achieve 1.25-meter resolution. To further boost resolution, the satellite employs super-resolution (SR), combining multiple low-resolution captures using sub-pixel shifts to produce high-resolution images. This technique, effective when images contain aliased high-frequency details, reconstructs full-resolution imagery using phase information from multiple observations, and has been successfully applied in remote sensing missions like SPOT-5, SkySat, and DubaiSat-1. A Monte Carlo simulation explores the factors influencing the resolution in Resourcesat-3S/3SA, with sensitivity analysis highlighting key impacts. The simulation methodology is broadly applicable to other remote sensing missions, optimizing SR for enhanced image clarity and resolution in future satellite systems., Comment: Preprint
- Published
- 2024
37. Scalable computation of input-normal/output-diagonal balanced realization for control-affine polynomial systems
- Author
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Corbin, Nicholas A., Sarkar, Arijit, Scherpen, Jacquelien M. A., and Kramer, Boris
- Subjects
Mathematics - Optimization and Control - Abstract
We present a scalable tensor-based approach to computing input-normal/output-diagonal nonlinear balancing transformations for control-affine systems with polynomial nonlinearities. This transformation is necessary to determine the states that can be truncated when forming a reduced-order model. Given a polynomial representation for the controllability and observability energy functions, we derive the explicit equations to compute a polynomial transformation to induce input-normal/output-diagonal structure in the energy functions in the transformed coordinates. The transformation is computed degree-by-degree, similar to previous Taylor-series approaches in the literature. However, unlike previous works, we provide a detailed analysis of the transformation equations in Kronecker product form to enable a scalable implementation. We derive the explicit algebraic structure for the equations, present rigorous analyses for the solvability and algorithmic complexity of those equations, and provide general purpose open-source software implementations for the proposed algorithms to stimulate broader use of nonlinear balanced truncation model. We demonstrate that with our efficient implementation, computing the nonlinear transformation is approximately as expensive as computing the energy functions., Comment: 11 pages, 6 figures
- Published
- 2024
38. PyTOPress: Python code for topology optimization with design-dependent pressure loads
- Author
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Saxena, Shivajay, Sarkar, Swagatam Islam, and Kumar, Prabhat
- Subjects
Computer Science - Computational Engineering, Finance, and Science - Abstract
Python is a low-cost and open-source substitute for the MATLAB programming language. This paper presents ``\texttt{PyTOPress}", a compact Python code for topology optimization that is primarily meant for pedagogical purposes. \texttt{PyTOPress}, based on the ``\texttt{TOPress}" MATLAB code \cite{kumar2023topress}, is built using the \texttt{NumPy} and \texttt{SciPy} libraries. The applied pressure load is modeled using the Darcy law and the drainage term. From the obtained pressure field, the constant nodal loads are found. The employed method makes it easier to compute the load sensitivity using the adjoint-variable method at a low cost. The topology optimization problems are resolved herein by minimizing the compliance of the structure with a constraint on material volume. The method of moving asymptotes is employed to update the design variables. The effectiveness and success of \texttt{PyTOPress} code are demonstrated by solving few design-dependent pressure loadbearing problems. The code is freely available at \url{https://github.com/PrabhatIn/PyTOPress}., Comment: Accepted in iNCMDAO 2024
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- 2024
39. User-Centered Design of Socially Assistive Robotic Combined with Non-Immersive Virtual Reality-based Dyadic Activities for Older Adults Residing in Long Term Care Facilities
- Author
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Ghosh, Ritam, Khan, Nibraas, Migovich, Miroslava, Tate, Judith A., Maxwell, Cathy, Latshaw, Emily, Newhouse, Paul, Scharre, Douglas W., Tan, Alai, Colopietro, Kelley, Mion, Lorraine C., and Sarkar, Nilanjan
- Subjects
Computer Science - Human-Computer Interaction ,Electrical Engineering and Systems Science - Systems and Control - Abstract
Apathy impairs the quality of life for older adults and their care providers. While few pharmacological remedies exist, current non-pharmacologic approaches are resource intensive. To address these concerns, this study utilizes a user-centered design (UCD) process to develop and test a set of dyadic activities that provide physical, cognitive, and social stimuli to older adults residing in long-term care (LTC) communities. Within the design, a novel framework that combines socially assistive robots and non-immersive virtual reality (SAR-VR) emphasizing human-robot interaction (HRI) and human-computer interaction (HCI) is utilized with the roles of the robots being coach and entertainer. An interdisciplinary team of engineers, nurses, and physicians collaborated with an advisory panel comprising LTC activity coordinators, staff, and residents to prototype the activities. The study resulted in four virtual activities: three with the humanoid robot, Nao, and one with the animal robot, Aibo. Fourteen participants tested the acceptability of the different components of the system and provided feedback at different stages of development. Participant approval increased significantly over successive iterations of the system highlighting the importance of stakeholder feedback. Five LTC staff members successfully set up the system with minimal help from the researchers, demonstrating the usability of the system for caregivers. Rationale for activity selection, design changes, and both quantitative and qualitative results on the acceptability and usability of the system have been presented. The paper discusses the challenges encountered in developing activities for older adults in LTCs and underscores the necessity of the UCD process to address them.
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- 2024
40. The Influence of Lepton Portal on the WIMP-pFIMP framework
- Author
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Lahiri, Jayita, Pradhan, Dipankar, and Sarkar, Abhik
- Subjects
High Energy Physics - Phenomenology - Abstract
The dynamics and detection possibility of a pseudo-FIMP (pFIMP) dark matter (DM) in the presence of a thermal DM have been studied in different contexts. The pFIMP phenomenology largely depends on the WIMP-like partner DM, as pFIMP interacts with the standard model (SM) particles only via the partner DM loop. Introducing a lepton portal interaction, which connects DM directly to the SM lepton sector, improves its detection prospects. However, such possibilities are constrained strongly by the non-observation of lepton flavor-violating decays. Interestingly, this also makes it possible to probe such models in future low-energy experiments. In this article, we have tried to establish such connections and find parameter space which respects the limits from DM relic, direct, indirect, and lepton flavor violation (LFV). We also recast the constraints from di-lepton/di-tau plus missing energy signal at the LHC on our model and provide projections for HL-LHC and future lepton colliders. Although the LFV and collider limits mainly concern WIMPs, the parameter space for pFIMPs is also constrained due to its strong connection to WIMPs through DM relic density and detection prospects., Comment: 26 pages, 13 figures, 3 tables
- Published
- 2024
41. A potpourri of results on molecular communication with active transport
- Author
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Dewan, Phanindra and Sarkar, Sumantra
- Subjects
Condensed Matter - Statistical Mechanics ,Condensed Matter - Soft Condensed Matter ,Computer Science - Emerging Technologies ,Electrical Engineering and Systems Science - Signal Processing ,Physics - Biological Physics - Abstract
Molecular communication (MC) is a model of information transmission where the signal is transmitted by information-carrying molecules through their physical transport from a transmitter to a receiver through a communication channel. Prior efforts have identified suitable "information molecules" whose efficacy for signal transmission has been studied extensively in diffusive channels (DC). Although easy to implement, DCs are inefficient for distances longer than tens of nanometers. In contrast, molecular motor-driven nonequilibrium or active transport can drastically increase the range of communication and may permit efficient communication up to tens of micrometers. In this paper, we investigate how active transport influences the efficacy of molecular communication, quantified by the mutual information between transmitted and received signals. We consider two specific scenarios: (a) active transport through relays and (b) active transport through a mixture of active and diffusing particles. In each case, we discuss the efficacy of the communication channel and discuss their potential pitfalls., Comment: 8 pages, 5 figures
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- 2024
42. Geometric Correction and Mosaic Generation of Geo High Resolution Camera Images
- Author
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Garg, Ankur, Thapa, Nitesh, Sangar, Ghansham, Gaur, Neha, Sarkar, Meenakshi, Moorthi, S. Manthira, and Dhar, Debajyoti
- Subjects
Electrical Engineering and Systems Science - Image and Video Processing - Abstract
The Geo High Resolution Camera (GHRC) aboard ISRO GSAT-29 satellite is a state-of-the-art 6-band Visible and Near Infrared (VNIR) imager in geostationary orbit at 55degE longitude. It provides a ground sampling distance of 55 meters at nadir, covering 110x110 km at a time, and can image the entire Earth disk using a scan mirror mechanism. To cover India, GHRC uses a two-dimensional raster scanning technique, resulting in over 1,000 scenes that must be stitched into a seamless mosaic. This paper presents the geolocation model and examines potential sources of targeting error, with an assessment of location accuracy. Challenges in inter-band registration and inter-frame mosaicing are addressed through algorithms for geometric correction, band-to-band registration, and seamless mosaic generation. In-flight geometric calibration, including adjustments to the instrument interior alignment angles using ground reference images, has improved pointing and location accuracy. A backtracking algorithm has been developed to correct frame-to-frame mosaicing errors for large-scale mosaics, leveraging geometric models, image processing, and space resection techniques. These advancements now enable the operational generation of full India mosaics with 100-meter resolution and high geometric fidelity, enhancing the GHRC capabilities for Earth observation and monitoring applications., Comment: Preprint
- Published
- 2024
43. Intention Is All You Need
- Author
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Sarkar, Advait
- Subjects
Computer Science - Human-Computer Interaction - Abstract
Among the many narratives of the transformative power of Generative AI is one that sees in the world a latent nation of programmers who need to wield nothing but intentions and natural language to render their ideas in software. In this paper, this outlook is problematised in two ways. First, it is observed that generative AI is not a neutral vehicle of intention. Multiple recent studies paint a picture of the "mechanised convergence" phenomenon, namely, that generative AI has a homogenising effect on intention. Second, it is observed that the formation of intention itself is immensely challenging. Constraints, materiality, and resistance can offer paths to design metaphors for intentional tools. Finally, existentialist approaches to intention are discussed and possible implications for programming are proposed in the form of a speculative, illustrative set of intentional programming practices., Comment: Proceedings of the 35th Annual Conference of the Psychology of Programming Interest Group (PPIG 2024)
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- 2024
44. Hyperspectral Spatial Super-Resolution using Keystone Error
- Author
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Garg, Ankur, Sarkar, Meenakshi, Moorthi, S. Manthira, and Dhar, Debajyoti
- Subjects
Electrical Engineering and Systems Science - Image and Video Processing - Abstract
Hyperspectral images enable precise identification of ground objects by capturing their spectral signatures with fine spectral resolution.While high spatial resolution further enhances this capability, increasing spatial resolution through hardware like larger telescopes is costly and inefficient. A more optimal solution is using ground processing techniques, such as hypersharpening, to merge high spectral and spatial resolution data. However, this method works best when datasets are captured under similar conditions, which is difficult when using data from different times. In this work, we propose a superresolution approach to enhance hyperspectral data's spatial resolution without auxiliary input. Our method estimates the high-resolution point spread function (PSF) using blind deconvolution and corrects for sampling-related blur using a model-based superresolution framework. This differs from previous approaches by not assuming a known highresolution blur. We also introduce an adaptive prior that improves performance compared to existing methods. Applied to the visible and near-infrared (VNIR) spectrometer of HySIS, ISRO hyperspectral sensor, our algorithm removes aliasing and boosts resolution by approximately 1.3 times. It is versatile and can be applied to similar systems., Comment: Preprint
- Published
- 2024
45. Advancements in Image Resolution: Super-Resolution Algorithm for Enhanced EOS-06 OCM-3 Data
- Author
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Garg, Ankur, Shukla, Tushar, Joshi, Purvee, Ganguly, Debojyoti, Gujarati, Ashwin, Sarkar, Meenakshi, Babu, KN, Pandya, Mehul, Moorthi, S. Manthira, and Dhar, Debajyoti
- Subjects
Electrical Engineering and Systems Science - Image and Video Processing ,Electrical Engineering and Systems Science - Signal Processing - Abstract
The Ocean Color Monitor-3 (OCM-3) sensor is instrumental in Earth observation, achieving a critical balance between high-resolution imaging and broad coverage. This paper explores innovative imaging methods employed in OCM-3 and the transformative potential of super-resolution techniques to enhance image quality. The super-resolution model for OCM-3 (SOCM-3) addresses the challenges of contemporary satellite imaging by effectively navigating the trade-off between image clarity and swath width. With resolutions below 240 meters in Local Area Coverage (LAC) mode and below 750 meters in Global Area Coverage (GAC) mode, coupled with a wide 1550-kilometer swath and a 2-day revisit time, SOCM-3 emerges as a leading asset in remote sensing. The paper details the intricate interplay of atmospheric, motion, optical, and detector effects that impact image quality, emphasizing the necessity for advanced computational techniques and sophisticated algorithms for effective image reconstruction. Evaluation methods are thoroughly discussed, incorporating visual assessments using the Blind/Referenceless Image Spatial Quality Evaluator (BRISQUE) metric and computational metrics such as Line Spread Function (LSF), Full Width at Half Maximum (FWHM), and Super-Resolution (SR) ratio. Additionally, statistical analyses, including power spectrum evaluations and target-wise spectral signatures, are employed to gauge the efficacy of super-resolution techniques. By enhancing both spatial resolution and revisit frequency, this study highlights significant advancements in remote sensing capabilities, providing valuable insights for applications across cryospheric, vegetation, oceanic, coastal, and domains. Ultimately, the findings underscore the potential of SOCM-3 to contribute meaningfully to our understanding of finescale oceanic phenomena and environmental monitoring., Comment: Preprint
- Published
- 2024
46. Lepton Collider as a window to Reheating: II
- Author
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Barman, Basabendu, Bhattacharya, Subhaditya, Jahedi, Sahabub, Pradhan, Dipankar, and Sarkar, Abhik
- Subjects
High Energy Physics - Phenomenology ,General Relativity and Quantum Cosmology ,High Energy Physics - Experiment - Abstract
Dark matter (DM) genesis via Ultraviolet (UV) freeze-in embeds the seed of reheating temperature and dynamics in its relic density. Thus, discovery of such a DM candidate can possibly open the window for post-inflationary dynamics. However, there are several challenges in this exercise, as freezing-in DM possesses feeble interaction with the visible sector and therefore very low production cross-section at the collider. We show that mono-photon (and dilepton) signal at the ILC, arising from DM effective operators connected to the SM field strength tensors, can still warrant a signal discovery. We study both the scalar and fermionic DM production during reheating via UV freeze-in, when the inflaton oscillates at the bottom of a general monomial potential. Interestingly, we see, right DM abundance can be achieved only in the case of bosonic reheating scenario, satisfying bounds from big bang nucleosynthesis (BBN). This provides a unique correlation between collider signal and the post-inflationary dynamics of the Universe within single-field inflationary models., Comment: 28 pages, 10 figures and 4 table
- Published
- 2024
47. Data Processing Chain and Products of EOS-06 OCM-3 Payload From Signal Processing to Geometric Precision
- Author
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Garg, Ankur, Shukla, Tushar, Arya, Sunita, Sangar, Ghansham, Roy, Sampa, Sarkar, Meenakshi, Moorthi, S. Manthira, and Dhar, Debajyoti
- Subjects
Electrical Engineering and Systems Science - Signal Processing - Abstract
The Ocean Color Monitor-3, launched aboard Oceansat-3, represents a significant advancement in ocean observation technology, building upon the capabilities of its predecessors. With thirteen spectral bands, OCM-3 enhances feature identification and atmospheric correction, enabling precise data collection from a sun-synchronous orbit. With thirteen spectral bands, OCM-3 enhances feature identification and atmospheric correction, enabling precise data collection from a sunsynchronous orbit. Operating at an altitude of 732.5 km, the satellite achieves high signal-to-noise ratios (SNR) through sophisticated onboard and ground processing techniques, including advanced geometric modeling for pixel registration.The OCM-3 processing pipeline, consisting of multiple levels, ensures rigorous calibration and correction of radiometric and geometric data. This paper presents key methodologies such as dark data modeling, photo response non-uniformity correction, and smear correction, are employed to enhance data quality. The effective implementation of ground time delay integration (TDI) allows for the refinement of SNR, with evaluations demonstrating that performance specifications were exceeded. Geometric calibration procedures, including band-to-band registration and geolocation accuracy assessments, which further optimize data reliability are presented in the paper. Advanced image registration techniques leveraging Ground Control Points (GCPs) and residual error analysis significantly reduce geolocation errors, achieving precision within specified thresholds. Overall, OCM-3 comprehensive calibration and processing strategies ensure high-quality, reliable data crucial for ocean monitoring and change detection applications, facilitating improved understanding of ocean dynamics and environmental changes., Comment: Preprint
- Published
- 2024
48. Efficient Scheduling of Vehicular Tasks on Edge Systems with Green Energy and Battery Storage
- Author
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Sarkar, Suvarthi, Ray, Abinash Kumar, and Sahu, Aryabartta
- Subjects
Computer Science - Distributed, Parallel, and Cluster Computing - Abstract
The autonomous vehicle industry is rapidly expanding, requiring significant computational resources for tasks like perception and decision-making. Vehicular edge computing has emerged to meet this need, utilizing roadside computational units (roadside edge servers) to support autonomous vehicles. Aligning with the trend of green cloud computing, these roadside edge servers often get energy from solar power. Additionally, each roadside computational unit is equipped with a battery for storing solar power, ensuring continuous computational operation during periods of low solar energy availability. In our research, we address the scheduling of computational tasks generated by autonomous vehicles to roadside units with power consumption proportional to the cube of the computational load of the server. Each computational task is associated with a revenue, dependent on its computational needs and deadline. Our objective is to maximize the total revenue of the system of roadside computational units. We propose an offline heuristics approach based on predicted solar energy and incoming task patterns for different time slots. Additionally, we present heuristics for real-time adaptation to varying solar energy and task patterns from predicted values for different time slots. Our comparative analysis shows that our methods outperform state-of-the-art approaches upto 40\% for real-life datasets.
- Published
- 2024
49. Dynamical interiors of Black-Bounce spacetimes
- Author
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Pal, Kunal, Pal, Kuntal, and Sarkar, Tapobrata
- Subjects
General Relativity and Quantum Cosmology ,High Energy Physics - Theory - Abstract
Using the Israel-Darmois junction conditions, we obtain a class of regular dynamical interiors to the recently proposed black-bounce spacetimes which regularises the Schwarzschild singularity by introducing a regularisation parameter. We show that a regularised Friedmann-Lemaitre-Robertson-Walker like interior geometry can not be matched smoothly with the exterior black-bounce spacetime through a timelike hypersurface, as there always exists a thin shell of non-zero energy-momentum tensor at the matching hypersurface. We obtain the expressions for the energy density and pressure of the thin shell energy-momentum tensor in terms of the regularisation parameter and derive an evolution equation for the scale factor of the interior geometry by imposing physical conditions on these components of the surface energy-momentum tensor. We also discuss the formation of the event horizon inside the interior in the case when the initial conditions are such that the situation describes a collapsing matter cloud. We elaborate upon the physical implications of these results.
- Published
- 2024
50. Effect of Magnetic Field on the Formation of Radiatively Inefficient Accretion Flow around Black Holes
- Author
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Sarkar, Anish and Pahari, Mayukh
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
We study the effects of magnetic field in the formation of a radiatively inefficient accretion flow (RIAF) in the presence of Bremsstrahlung cooling, which facilitates the formation of a geometrically thin, optically thick accretion disk surrounded by a hot corona. We have performed axis-symmetric magnetohydrodynamic (MHD) simulations of an initial accretion torus with a $1/r$ dependant local poloidal field in the presence of a pseudo-Newtonian potential, taking into account optically thin cooling, resistivity and viscosity. We observe the formation of persistent jets and magnetised outflows from the corona surrounding a thin disk with an increase in the magnetic diffusivity parameter. We have defined an equivalent time scale ($\tau_{eq}$) which takes into account the heating time scales due to viscosity, resistivity, magnetic reconnection and magneto-rotational instability turbulence such that the thin disk is formed if the cooling time scale ($\tau_{cool}$) is lower than this equivalent time scale ($\tau_{cool}/\tau_{eq}<1$). Using this condition, for the first time, we found that the thin disk exists when the initial ratio of plasma pressure to magnetic pressure (plasma beta) exceeds a range of $600-800$ for the gas obeying a polytropic equation of state accreting at $10^{-5}\ M_{\odot}/year$, Comment: Comments are welcome
- Published
- 2024
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