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173 results on '"Prakash, Arjun"'

2. Convex-Concave Zero-sum Markov Stackelberg Games

Author

Goktas, Denizalp, Prakash, Arjun, and Greenwald, Amy

Subjects
Computer Science - Computer Science and Game Theory
Abstract

Zero-sum Markov Stackelberg games can be used to model myriad problems, in domains ranging from economics to human robot interaction. In this paper, we develop policy gradient methods that solve these games in continuous state and action settings using noisy gradient estimates computed from observed trajectories of play. When the games are convex-concave, we prove that our algorithms converge to Stackelberg equilibrium in polynomial time. We also show that reach-avoid problems are naturally modeled as convex-concave zero-sum Markov Stackelberg games, and that Stackelberg equilibrium policies are more effective than their Nash counterparts in these problems.

Published
2024

5. On the Fairness of 'Fake' Data in Legal AI

Author

Boswell, Lauren and Prakash, Arjun

Subjects
Computer Science - Computers and Society, Computer Science - Artificial Intelligence
Abstract

The economics of smaller budgets and larger case numbers necessitates the use of AI in legal proceedings. We examine the concept of disparate impact and how biases in the training data lead to the search for fairer AI. This paper seeks to begin the discourse on what such an implementation would actually look like with a criticism of pre-processing methods in a legal context . We outline how pre-processing is used to correct biased data and then examine the legal implications of effectively changing cases in order to achieve a fairer outcome including the black box problem and the slow encroachment on legal precedent. Finally we present recommendations on how to avoid the pitfalls of pre-processed data with methods that either modify the classifier or correct the output in the final step., Comment: Submitted to the Artificial Intelligence Ethics Journal

Published
2020

6. Structural clustering of volatility regimes for dynamic trading strategies

Author

Prakash, Arjun, James, Nick, Menzies, Max, and Francis, Gilad

Subjects
Quantitative Finance - Statistical Finance, Computer Science - Computational Engineering, Finance, and Science, Computer Science - Machine Learning, Quantitative Finance - Risk Management
Abstract

We develop a new method to find the number of volatility regimes in a nonstationary financial time series by applying unsupervised learning to its volatility structure. We use change point detection to partition a time series into locally stationary segments and then compute a distance matrix between segment distributions. The segments are clustered into a learned number of discrete volatility regimes via an optimization routine. Using this framework, we determine a volatility clustering structure for financial indices, large-cap equities, exchange-traded funds and currency pairs. Our method overcomes the rigid assumptions necessary to implement many parametric regime-switching models, while effectively distilling a time series into several characteristic behaviours. Our results provide significant simplification of these time series and a strong descriptive analysis of prior behaviours of volatility. Finally, we create and validate a dynamic trading strategy that learns the optimal match between the current distribution of a time series and its past regimes, thereby making online risk-avoidance decisions in the present., Comment: Accepted manuscript

Published
2020
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9. Disparity in employment in India: evidence from engineering graduates across social groups and gender.

Author

Prakash, Arjun and Yadav, Inder Sekhar

Subjects
*CASTE discrimination, *SOCIAL groups, *SEX discrimination, *GENDER inequality, *ACADEMIC employment
Abstract

The study scrutinises caste and gender disparity in shaping employment outcomes and academic performances across 1406 students from a prestigious engineering college in Kerala, India, employing logistic regression of campus recruitment data. The study reveals that students from marginalised social groups experience significantly lower placement rates and exhibit substantially lower academic performance. Even after accounting for academic differences, marginalised community students are less likely to be employed, signalling labour market bias. Males within this marginalised group face even lower placement chances. When employed, marginalised group students are less likely to be employed in high-paying jobs. Interestingly, while females are preferred over males, especially in high-paying jobs, they are underrepresented in the engineering domain, particularly in the branches that are traditionally male-dominated. The study is among the first to comprehensively examine the interplay of multiple factors – employment disparity, wage levels, academic performances, caste and gender in campus recruitment. [ABSTRACT FROM AUTHOR]

Published
2024
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10. Real-Time Video Surveillance for Safety Line and Pedestrian Breach Detection in a Dynamic Environment

Author

Prakash, Arjun, Verma, Santosh, Vijay, Shivam, Angrisani, Leopoldo, Series Editor, Arteaga, Marco, Series Editor, Panigrahi, Bijaya Ketan, Series Editor, Chakraborty, Samarjit, Series Editor, Chen, Jiming, Series Editor, Chen, Shanben, Series Editor, Chen, Tan Kay, Series Editor, Dillmann, Ruediger, Series Editor, Duan, Haibin, Series Editor, Ferrari, Gianluigi, Series Editor, Ferre, Manuel, Series Editor, Hirche, Sandra, Series Editor, Jabbari, Faryar, Series Editor, Jia, Limin, Series Editor, Kacprzyk, Janusz, Series Editor, Khamis, Alaa, Series Editor, Kroeger, Torsten, Series Editor, Liang, Qilian, Series Editor, Ming, Tan Cher, Series Editor, Minker, Wolfgang, Series Editor, Misra, Pradeep, Series Editor, Möller, Sebastian, Series Editor, Mukhopadhyay, Subhas, Series Editor, Ning, Cun-Zheng, Series Editor, Nishida, Toyoaki, Series Editor, Pascucci, Federica, Series Editor, Qin, Yong, Series Editor, Seng, Gan Woon, Series Editor, Veiga, Germano, Series Editor, Wu, Haitao, Series Editor, Zhang, Junjie James, Series Editor, Rawat, Banmali S., editor, Trivedi, Aditya, editor, Manhas, Sanjeev, editor, and Karwal, Vikram, editor

Published
2019
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17. Post Thawing Survival Rate Of Human Embryos In Slow Freezing Versus Vitrification: A Narrative Review

Author

Unnikrishnan, Aishwarya Grace, Baqri, Maryam Irshad, Ranjith, Navneeth, Khaleelullah, Afifa, Sait, Nazneen Naveed, Rehmani, Madiha Bano, Prakash, Arjun Jay, Unnikrishnan, Alina Grace, Unnikrishnan, Aishwarya Grace, Baqri, Maryam Irshad, Ranjith, Navneeth, Khaleelullah, Afifa, Sait, Nazneen Naveed, Rehmani, Madiha Bano, Prakash, Arjun Jay, and Unnikrishnan, Alina Grace

Abstract

The study compared the outcomes of slow-freeze and vitrification methods for oocyte cryopreservation, analyzing five randomized controlled trials, two cohort studies, and eight systematic reviews and meta-analyses.Slow-freezeis performed at room temperature using a buffered medium supplemented with gentamicin and human serum albumin. It contains 1.5 M 1,2-propanediol and 0.1 M sucrose. On the other hand, vitrification has been the preferred method since 2007. During vitrification, embryos are initially incubated in a solution consisting of 7.5% ethylene glycol and 7.5% dimethyl sulfide, both in Ham's F-10 media. This solution is further supplemented with 20% Albuminal-5. After the initial recovery, the oocytes are aspirated and immersed in a vitrification solution composed of Ham's F-10 medium for a duration of 50 to 60 seconds. The cooling is done via liquid nitrogen, and embryos are stored for months. The survival rate of embryos is the percentage of those that survive after being warmed up. Live birth rates are calculated as the percentage of live births per transferred embryo and warmed embryo. Embryos are selected by biopsy at the zygote or blastocyst stage using non-invasive methods to optimize the success rates of in vitro fertilization. Vitrification has a greater success rate, better survival rates, and transferable embryos, it is chosen for oocyte cryopreservation. Better clinical pregnancy rates and implantation capacity have also been linked to it, notably for blastocysts from In Vitro Maturation programs. To assess effects on neonatal outcomes and congenital abnormalities, additional study is necessary.

Published
2023

24. Understanding ASPECTS of stroke: Inter-rater reliability between emergency medicine physician and radiologist in a rural setup.

Author

Nimmalapudi, Sunanda, Inampudi, Vineel, Prakash, Arjun, Gowda, Rajesh, and Varadharajan, Shriram

Abstract

Purpose: The purpose is to determine the inter-rater reliability in grading ASPECTS score, between emergency medicine physician at first contact and radiologist among patients with acute ischemic stroke. Materials and Methods: We conducted a prospective analysis of 765 acute ischemic stroke cases referred to the Department of Radiodiagnosis in a rural-based hospital in South India, during January 2017 to October 2021. Non-contrast computed tomography (NCCT) scans of the brain were performed using GE Bright Speed Elite 128 Slice CT Scanner. ASPECTS score was calculated separately by an emergency medicine physician and radiologist. Inter-rater reliability for total and dichotomized ASPECTS (≥6 and <6) scores were assessed using statistical analysis (ICC and Cohen ĸ coefficients) on SPSS software (v17.0). Results: Inter-rater agreement for total and dichotomized ASPECTS was substantial (ICC 0.79 and Cohen ĸ 0.68) between the emergency physician and the radiologist. Mean difference in ASPECTS between the two readers was only 0.15 with standard deviation of 1.58. No proportionality bias was detected. The Bland–Altman plot was constructed to demonstrate the distribution of ASPECTS differences between the two readers. Conclusion: Substantial inter-rater agreement was noted in grading ASPECTS between emergency medicine physician at first contact and radiologist, thereby confirming its robustness even in a rural setting. [ABSTRACT FROM AUTHOR]

Published
2023
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39. Bimelic symmetric Hirayama disease: Spectrum of magnetic resonance imaging findings and comparative evaluation with classical monomelic amyotrophy and other motor neuron disease

Author

Boruah, Deb Kumar, Sanyal, Shantiranjan, Prakash, Arjun, Achar, Sashidhar, Dhingani, Dhabal D., and Sarma, Binod

Subjects
Anterior Horn Cells, Lamino-Dural Space, Amyotrophic Lateral Sclerosis, Original Article, Monomelic Amyotrophy, Wasting
Abstract

Background: The aim of the study was to evaluate the magnetic resonance imaging (MRI) findings in bilateral symmetrical Hirayama disease and find out MRI features which are probably more indicative of symmetrical Hirayama disease, thereby help in differentiating this entity from other motor neuron disease (MND). Methods: This prospective as well as retrospective study was carried out from December 2010 to September 2016 in a tertiary care center of northeast India on 92 patients with Hirayama disease. Only 19 patients having bilateral symmetric upper limb involvement at the time of presentation were included in this study sample. Results: Nineteen patients, who constituted 20.6% of 92 patients of clinical and flexion MRI confirmed Hirayama disease were found to have bilateral symmetrical wasting and weakness of distal upper limb muscles at the time of presentation. Mean ± standard deviation (SD) age of onset of the disease process was 21.7 ± 3.8 years with mean ± SD duration of illness of 3.6 ± 1.3 years. MRI revealed lower cervical cord flattening in 13 (68.4%) patients which was symmetrical in 6 (31.6%) patients and asymmetrical in 7 (36.8%) patients. In the majority of these patients, T2-weighted images (T2WI) cervical cord hyperintensities were found extending from C5 to C6 vertebral level. Seven (36.8%) patients in our study showed bilateral symmetric T2WI hyperintensities in anterior horn cells (AHC). Conclusion: Bilateral symmetrical involvement of Hirayama disease is an uncommon presentation. Symmetrical cervical cord flattening, T2WI cord and/or bilateral AHC hyperintensities were the major MRI findings detected. Flexion MRI demonstrated similar findings in both bimelic amyotrophy and classical unilateral amyotrophy. However, flexion MRI produced some distinguishing features more typical for bilateral symmetrical Hirayama disease which help to differentiate it from other MNDs.

Published
2017

40. Magnetic resonance imaging evaluation of posterior spinal tuberculosis: a cross-sectional study.

Author

Boruah, Deb K, Gogoi, Bidyut B, Prakash, Arjun, Lal, Navneet R, Hazarika, Karuna, and Borah, Krishna K

Subjects
SPINAL tuberculosis, MAGNETIC resonance imaging, EPIDURAL abscess, THORACIC vertebrae, CERVICAL vertebrae, ZYGAPOPHYSEAL joint
Abstract

Background: Isolated posterior spinal (element) tuberculosis (TB) is uncommon compared to classical anterior spinal or para-discal TB. Here, we report magnetic resonance imaging (MRI) findings of posterior spinal TB in 19 patients without involvement of the vertebral body and intervertebral disc. Purpose: To evaluate the MRI findings in isolated posterior spinal (element) TB. Material and Methods: Clinical and MRI data of 19 patients of isolated posterior spinal TB were retrospectively evaluated. Results: Of the 19 patients, group A comprised 4 (21%) patients with rapid onset lower limb weakness and pyramidal signs while group B comprised 15 (79%) patients without any neurological deficit. Lumbar vertebrae commonly affected 9 (47.4%) patients followed by dorsal vertebrae in 8 (42.1%) patients and cervical vertebrae in 2 (10.5%) patients. The pedicle was most commonly involved in 12 (63.2%) patients followed by the lamina in 11 (58%) patients, and spinous process and facet joint in 6 (31.6%) patients each. Extra-spinal inflammation/pyomyositis/paraspinal abscess was found in 13 (68.4%) patients followed by epidural abscess 3 (15.8%) patients and both extra spinal inflammation and epidural abscess in 3 (15.8%) patients (15.8%). Compressive cord myelopathy was observed in 4 (21%) patients, where three patients underwent emergency decompression laminectomy and the remaining 16 patients were treated conservatively with anti-tubercular therapy. Conclusion: Initial diagnosis of isolated posterior element TB is challenging and requires a high index of suspicion. Early diagnosis of isolated posterior spinal TB is important as early treatment may be beneficial and decreases patient morbidity. [ABSTRACT FROM AUTHOR]

Published
2021
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