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Results for "Urvashi Khandelwal"

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What Does BERT Look At? An Analysis of BERT's AttentionJun 11 2019Large pre-trained neural networks such as BERT have had great recent success in NLP, motivating a growing body of research investigating what aspects of language they are able to learn from unlabeled data. Most recent analysis has focused on model outputs ... More
Sample Efficient Text Summarization Using a Single Pre-Trained TransformerMay 21 2019Language model (LM) pre-training has resulted in impressive performance and sample efficiency on a variety of language understanding tasks. However, it remains unclear how to best use pre-trained LMs for generation tasks such as abstractive summarization, ... More
BAM! Born-Again Multi-Task Networks for Natural Language UnderstandingJul 10 2019It can be challenging to train multi-task neural networks that outperform or even match their single-task counterparts. To help address this, we propose using knowledge distillation where single-task models teach a multi-task model. We enhance this training ... More
Sharp Nearby, Fuzzy Far Away: How Neural Language Models Use ContextMay 12 2018We know very little about how neural language models (LM) use prior linguistic context. In this paper, we investigate the role of context in an LSTM LM, through ablation studies. Specifically, we analyze the increase in perplexity when prior context words ... More
Assessing Vaccination Sentiments with Online Social Media: Implications for Infectious Disease Dynamics and ControlMay 23 2011Jul 30 2011There is great interest in the dynamics of health behaviors in social networks and how they affect collective public health outcomes, but measuring population health behaviors over time and space requires substantial resources. Here, we use publicly available ... More
AttentionRNN: A Structured Spatial Attention MechanismMay 22 2019Visual attention mechanisms have proven to be integrally important constituent components of many modern deep neural architectures. They provide an efficient and effective way to utilize visual information selectively, which has shown to be especially ... More
A multi-scale multi-frequency deconvolution algorithm for synthesis imaging in radio interferometryJun 14 2011Aims : We describe MS-MFS, a multi-scale multi-frequency deconvolution algorithm for wide-band synthesis-imaging, and present imaging results that illustrate the capabilities of the algorithm and the conditions under which it is feasible and gives accurate ... More
Computational Design of Finite Strain Auxetic Metamaterials via Topology Optimization and Nonlinear HomogenizationApr 25 2019A novel computational framework for designing metamaterials with negative Poisson's ratio over a large strain range is presented in this work by combining the density-based topology optimization together with a mixed stress/deformation driven nonlinear ... More
Faster K-Means Cluster EstimationJan 17 2017There has been considerable work on improving popular clustering algorithm `K-means' in terms of mean squared error (MSE) and speed, both. However, most of the k-means variants tend to compute distance of each data point to each cluster centroid for every ... More
Reconstruction Conjecture for Graphs Isomorphic to Cube of a TreeJul 08 2012This paper proves the reconstruction conjecture for graphs which are isomorphic to the cube of a tree. The proof uses the reconstructibility of trees from their peripheral vertex deleted subgraphs. The main result follows from (i) characterization of ... More
Deep wideband single pointings and mosaics in radio interferometry - How accurately do we reconstruct intensities and spectral indices of faint sources?May 24 2016Many deep wide-band wide-field radio interferometric surveys are being designed to accurately measure intensities, spectral indices and polarization properties of faint source populations. In this paper we compare various wideband imaging methods to evaluate ... More
Linear Bandits with Feature FeedbackMar 09 2019Mar 12 2019This paper explores a new form of the linear bandit problem in which the algorithm receives the usual stochastic rewards as well as stochastic feedback about which features are relevant to the rewards, the latter feedback being the novel aspect. The focus ... More
A joint deconvolution algorithm to combine single dish and interferometer data for wideband multi-term and mosaic imagingApr 18 2019Imaging in radio astronomy is usually carried out with a single-dish radio telescope doing a raster scan of a region of the sky or with an interferometer that samples the visibility function of the sky brightness. Mosaic observations are the current standard ... More
Linear Bandits with Feature FeedbackMar 09 2019This paper explores a new form of the linear bandit problem in which the algorithm receives the usual stochastic rewards as well as stochastic feedback about which features are relevant to the rewards, the latter feedback being the novel aspect. The focus ... More
Wideband Mosaic Imaging with the VLA - quantifying faint source imaging accuracyMar 20 2014A large number of deep and wide-field radio interferometric surveys are being designed to measure accurate statistics of faint source populations. Most require mosaic observations, and expect to benefit from the sensitivity provided by broad-band instruments. ... More
Improving Distantly Supervised Relation Extraction using Word and Entity Based AttentionApr 19 2018Relation extraction is the problem of classifying the relationship between two entities in a given sentence. Distant Supervision (DS) is a popular technique for developing relation extractors starting with limited supervision. We note that most of the ... More
VUPIC: Virtual Machine Usage Based Placement in IaaS CloudDec 01 2012Efficient resource allocation is one of the critical performance challenges in an Infrastructure as a Service (IaaS) cloud. Virtual machine (VM) placement and migration decision making methods are integral parts of these resource allocation mechanisms. ... More
ORBIT: Ordering Based Information Transfer Across Space and Time for Global Surface Water MonitoringNov 15 2017Many earth science applications require data at both high spatial and temporal resolution for effective monitoring of various ecosystem resources. Due to practical limitations in sensor design, there is often a trade-off in different resolutions of spatio-temporal ... More
Equivalent Dual Theories for 3D N=2 SupergravityJul 11 2019N=2 three dimensional Supergravity with internal $R-$symmetry generators can be understood as a two dimensional chiral Wess-Zumino-Witten model. In this paper, we present the reduced phase space description of the theory, which turns out to be flat limit ... More
Data-driven Modelling of Dynamical Systems Using Tree Adjoining Grammar and Genetic ProgrammingApr 05 2019State-of-the-art methods for data-driven modelling of non-linear dynamical systems typically involve interactions with an expert user. In order to partially automate the process of modelling physical systems from data, many EA-based approaches have been ... More
Evolving Clustered Random NetworksAug 04 2008We propose a Markov chain simulation method to generate simple connected random graphs with a specified degree sequence and level of clustering. The networks generated by our algorithm are random in all other respects and can thus serve as generic models ... More
Robust Fault Diagnosis by Optimal Input Design for Self-sensing SystemsMar 21 2017This paper presents a methodology for model based robust fault diagnosis and a methodology for input design to obtain optimal diagnosis of faults. The proposed algorithm is suitable for real time implementation. Issues of robustness are addressed for ... More
Grammar-based Representation and Identification of Dynamical SystemsNov 26 2018In this paper we propose a novel approach to identify dynamical systems. The method estimates the model structure and the parameters of the model simultaneously, automating the critical decisions involved in identification such as model structure and ... More
On the Simulation of Polynomial NARMAX ModelsOct 16 2018In this paper, we show that the common approach for simulation non-linear stochastic models, commonly used in system identification, via setting the noise contributions to zero results in a biased response. We also demonstrate that to achieve unbiased ... More
Automated Monitoring Cropland Using Remote Sensing Data: Challenges and Opportunities for Machine LearningApr 08 2019This paper provides an overview of how recent advances in machine learning and the availability of data from earth observing satellites can dramatically improve our ability to automatically map croplands over long period and over large regions. It discusses ... More
Direction Dependent Effects In Wide-Field Wideband Full Stokes Radio ImagingNov 05 2014Nov 17 2014Synthesis imaging in radio astronomy is affected by instrumental and atmospheric effects which introduce direction-dependent (DD) gains.The antenna power pattern varies both as a function of time and frequency. The broad band time varying nature of the ... More
Model Selection for Simulator-based Statistical Models: A Kernel ApproachFeb 07 2019We propose a novel approach to model selection for simulator-based statistical models. The proposed approach defines a mixture of candidate models, and then iteratively updates the weight coefficients for those models as well as the parameters in each ... More
General relativistic time dilation and increased uncertainty in generic quantum clocksApr 03 2019The theory of relativity associates a proper time with each moving object via its world line. In quantum theory however, such well-defined trajectories are forbidden. After introducing a general characterisation of quantum clocks, we demonstrate that, ... More
Why my photos look sideways or upside down? Detecting Canonical Orientation of Images using Convolutional Neural NetworksDec 04 2017Image orientation detection requires high-level scene understanding. Humans use object recognition and contextual scene information to correctly orient images. In literature, the problem of image orientation detection is mostly confronted by using low-level ... More
Exhaustive Verification of Weak Reconstruction For Self Complementary GraphsDec 29 2010This paper presents an exhaustive approach for verification of the weak reconstruction of Self Complementary Graphs up to 17 vertices. It describes the general problem of the Reconstruction Conjecture, explaining the complexity involved in checking deck-isomorphism ... More
Discovery of Shifting Patterns in Sequence ClassificationDec 19 2017In this paper, we investigate the multi-variate sequence classification problem from a multi-instance learning perspective. Real-world sequential data commonly show discriminative patterns only at specific time periods. For instance, we can identify a ... More
An Automatic Method for Complete Brain Matter Segmentation from Multislice CT scanSep 11 2018Oct 22 2018Computed tomography imaging is well accepted for its imaging speed, image contrast & resolution and cost. Thus it has wide use in detection and diagnosis of brain diseases. But unfortunately reported works on CT segmentation is not very significant. In ... More
Magnetization study to probe the effect of N2+ irradiation on Fe/Co bilayersFeb 28 2012Fe/Co bilayers were made using ion beam sputtering and then were subjected to nitrogen-ion irradiation to explore the influence of irradiation on their magnetic properties. Magnetization studies of Fe/Co bilayers along with their irradiated counterparts ... More
Smart Radio Spectrum Management for Cognitive RadioAug 06 2011Today's wireless networks are characterized by fixed spectrum assignment policy. The limited available spectrum and the inefficiency in the spectrum usage necessitate a new communication paradigm to exploit the existing wireless spectrum opportunistically. ... More
Task Planning in Robotics: an Empirical Comparison of PDDL-based and ASP-based SystemsApr 23 2018Feb 25 2019Robots need task planning algorithms to sequence actions toward accomplishing goals that are impossible through individual actions. Off-the-shelf task planners can be used by intelligent robotics practitioners to solve a variety of planning problems. ... More
Dynamic Clustering Protocol for Data Forwarding in Wireless Sensor NetworksJun 05 2013Energy being the very key concern area with sensor networks, so the main focus lies in developing a mechanism to increase the lifetime of a sensor network by energy balancing. To achieve energy balancing and maximizing network lifetime we use an idea ... More
The Dynamics of Health Behavior Sentiments on a Large Online Social NetworkJul 31 2012Modifiable health behaviors, a leading cause of illness and death in many countries, are often driven by individual beliefs and sentiments about health and disease. Individual behaviors affecting health outcomes are increasingly modulated by social networks, ... More
Exploiting Test Time Evidence to Improve Predictions of Deep Neural NetworksNov 24 2018Many prediction tasks, especially in computer vision, are often inherently ambiguous. For example, the output of semantic segmentation may depend on the scale one is looking at, and image saliency or video summarization is often user or context dependent. ... More
A Compressed Sensing Based Decomposition of Electro-Dermal Activity SignalsFeb 24 2016The measurement and analysis of Electro-Dermal Activity (EDA) offers applications in diverse areas ranging from market research, to seizure detection, to human stress analysis. Unfortunately, the analysis of EDA signals is made difficult by the superposition ... More
A Compressed Sensing Based Decomposition of Electrodermal Activity SignalsFeb 24 2016Jan 26 2017The measurement and analysis of Electrodermal Activity (EDA) offers applications in diverse areas ranging from market research, to seizure detection, to human stress analysis. Unfortunately, the analysis of EDA signals is made difficult by the superposition ... More
An English-Hindi Code-Mixed Corpus: Stance Annotation and Baseline SystemMay 30 2018Social media has become one of the main channels for peo- ple to communicate and share their views with the society. We can often detect from these views whether the person is in favor, against or neu- tral towards a given topic. These opinions from social ... More
Deep Radio Continuum Imaging of the Dwarf Irregular Galaxy IC10: Tracing Star Formation and Magnetic FieldsAug 01 2011We exploit the vastly increased sensitivity of the Expanded Very Large Array (EVLA) to study the radio continuum and polarization properties of the post-starburst, dwarf irregular galaxy IC10 at 6 cm, at a linear resolution of ~50 pc. We find close agreement ... More
Ultraslow Electron Spin Dynamics in GaAs Quantum Wells Probed by Optically Pumped NMRJul 19 1999Jul 20 1999Optically pumped nuclear magnetic resonance (OPNMR) measurements were performed in two different electron-doped multiple quantum well samples near the fractional quantum Hall effect ground state nu=1/3. Below 0.5K, the spectra provide evidence that spin-reversed ... More
MESH: A Flexible Distributed Hypergraph Processing SystemApr 01 2019With the rapid growth of large online social networks, the ability to analyze large-scale social structure and behavior has become critically important, and this has led to the development of several scalable graph processing systems. In reality, however, ... More
Optically Pumped NMR Measurements of the Electron Spin Polarization in GaAs Quantum Wells near Landau Level Filling Factor nu=1/3Jan 20 1998Jul 20 1998The Knight shift of Ga-71 nuclei is measured in two different electron-doped multiple quantum well samples using optically pumped NMR. These data are the first direct measurements of the electron spin polarization, P(nu,T)=<Sz(nu,T)>/max<Sz>, near nu=1/3. ... More
MESH: A Flexible Distributed Hypergraph Processing SystemApr 01 2019May 10 2019With the rapid growth of large online social networks, the ability to analyze large-scale social structure and behavior has become critically important, and this has led to the development of several scalable graph processing systems. In reality, however, ... More
Spectroscopic Evidence for the Localization of Skyrmions near Nu=1 as T->0Sep 08 2000Apr 02 2002Optically pumped nuclear magnetic resonance measurements of Ga-71 spectra were carried out in an n-doped GaAs/Al0.1Ga0.9As multiple quantum well sample near the integer quantum Hall ground state Nu=1. As the temperature is lowered (down to T~0.3 K), a ... More
A Radio Continuum Study of Dwarf Galaxies: 6 cm imaging of Little ThingsJan 16 2018In this paper we examine to what extent the radio continuum can be used as an extinction free probe of star formation in dwarf galaxies. To that aim we observe $40$ nearby dwarf galaxies with the Very Large Array at 6 cm ($4$-$8$ GHz) in C-configuration. ... More
A Corpus of English-Hindi Code-Mixed Tweets for Sarcasm DetectionMay 30 2018Social media platforms like twitter and facebook have be- come two of the largest mediums used by people to express their views to- wards different topics. Generation of such large user data has made NLP tasks like sentiment analysis and opinion mining ... More
The Population of Compact Radio Sources in the Orion Nebula ClusterMar 17 2016We present a deep centimeter-wavelength catalog of the Orion Nebula Cluster (ONC), based on a 30h single-pointing observation with the Karl G. Jansky Very Large Array in its high-resolution A-configuration using two 1 GHz bands centered at 4.7 GHz and ... More
MedAL: Deep Active Learning Sampling Method for Medical Image AnalysisSep 25 2018Sep 28 2018Deep learning models have been successfully used in medical image analysis problems but they require a large amount of labeled images to obtain good performance.Deep learning models have been successfully used in medical image analysis problems but they ... More
Optically Pumped NMR Studies of Electron Spin Polarization and Dynamics: New Constraints on the Composite Fermion Description of nu = 1/2Jul 19 1999The Knight shift and the nuclear spin-lattice relaxation rate 1/T1 of Ga-71 nuclei are measured in GaAs quantum wells at Landau level filling factor nu = 1/2 using optically pumped NMR. The temperature dependences of these data are compared with predictions ... More
The non-thermal superbubble in IC 10: the generation of cosmic ray electrons caught in the actNov 06 2014Nov 24 2014Superbubbles are crucial for stellar feedback, with supposedly high (of the order of 10 per cent) thermalization rates. We combined multiband radio continuum observations from the Very Large Array (VLA) with Effelsberg data to study the non-thermal superbubble ... More
Max-Margin Feature SelectionJun 14 2016Many machine learning applications such as in vision, biology and social networking deal with data in high dimensions. Feature selection is typically employed to select a subset of features which im- proves generalization accuracy as well as reduces the ... More
Understanding Systematic Errors Through Modeling of ALMA Primary BeamsJan 13 2017Feb 04 2017Many aspects of the Atacama Large Millimeter Array (ALMA) instrument are still unknown due to its young age. One such aspect is the true nature of the primary beam of each baseline, and how changes to the individual primary beams affect astronomical observations ... More
Block CUR: Decomposing Matrices using Groups of ColumnsMar 17 2017Jul 09 2018A common problem in large-scale data analysis is to approximate a matrix using a combination of specifically sampled rows and columns, known as CUR decomposition. Unfortunately, in many real-world environments, the ability to sample specific individual ... More
Cloud Programming Simplified: A Berkeley View on Serverless ComputingFeb 09 2019Serverless cloud computing handles virtually all the system administration operations needed to make it easier for programmers to use the cloud. It provides an interface that greatly simplifies cloud programming, and represents an evolution that parallels ... More
Wideband VLA Observations of Abell 2256 I: Continuum, Rotation Measure and Spectral ImagingAug 25 2014We report new observations of Abell 2256 with the Karl G. Jansky Very Large Array (VLA) at frequencies between 1 and 8 GHz. These observations take advantage of the 2:1 bandwidths available for a single observation to study the spectral index, polarization ... More
Extreme radio flares and associated X-ray variability from young stellar objects in the Orion Nebula ClusterJun 17 2017Young stellar objects are known to exhibit strong radio variability on timescales of weeks to months, and a few reports have documented extreme radio flares, with at least an order of magnitude change in flux density on timescales of hours to days. However, ... More
Measurement of the real dielectric permittivity epsilon_r of glacial iceDec 08 2017Jan 14 2019Using data collected by the Askaryan Radio Array (ARA) experiment at the South Pole, we have used long-baseline propagation of radio-frequency signals to extract information on the radio-frequency index-of-refraction in South Polar ice. Owing to the increasing ... More
Design and Performance of an Interferometric Trigger Array for Radio Detection of High-Energy NeutrinosSep 12 2018Oct 22 2018Ultra-high energy neutrinos are detectable through impulsive radio signals generated through interactions in dense media, such as ice. Subsurface in-ice radio arrays are a promising way to advance the observation and measurement of astrophysical high-energy ... More
Observation of Reconstructable Radio Emission Coincident with an X-Class Solar Flare in the Askaryan Radio Array Prototype StationJul 09 2018The Askaryan Radio Array (ARA) reports an observation of radio emission coincident with the "Valentine's Day" solar flare on Feb. 15$^{\rm{th}}$, 2011 in the prototype "Testbed" station. We find $\sim2000$ events that passed our neutrino search criteria ... More