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2795588361,115 · Jun 202019922001200920172026
48 results for Data sketching

We introduce a new sub-linear space sketch---the Weight-Median Sketch---for learning compressed linear classifiers over data streams while supporting the efficient recovery of large-magnitude weights in the model. This enables memory-limited execution of several statistical analyses over streams, including online featu…

2017-11-07abs ↗pdf ↗

Sketch-BERT learns vector sketches using BERT-like self-supervised learning.

problem Lack of effective vector sketch representation for recognition and retrieval tasks.
method Generalized BERT to sketch domain with novel embedding networks and self-supervised sketch gestalt learning.
result Improved performance on sketch recognition, retrieval, and gestalt tasks.

A new data-oblivious sketch for logistic regression reduces data size while maintaining approximation accuracy.

problem Efficiently solving logistic regression in one pass over a data stream.
method Data-oblivious sketching approach that reduces data size to poly(μdlog n) weighted points.
result Sketching reduces data size significantly and provides approximation guarantees.

Localized sketching improves matrix multiplication and ridge regression complexity.

problem Efficiently approximate matrix multiplication and ridge regression with limited data availability.
method Localized sketching matrices for block diagonal structure, reducing sample complexity.
result Localized sketching achieves sample complexity matching global sketching methods.

New guarantees for asymmetric sketching in compressive learning.

problem Statistical guarantees for compressive learning with asymmetric feature maps.
method Proves existing guarantees carry over to asymmetric scheme with LPD property, applies to quantized sketches.
result Existing statistical guarantees for compressive learning extend to asymmetric schemes with controlled error.

Recently, randomly mapping vectorial data to strings of discrete symbols (i.e., sketches) for fast and space-efficient similarity searches has become popular. Such random mapping is called similarity-preserving hashing and approximates a similarity metric by using the Hamming distance. Although many efficient similarit…

2019-10-18abs ↗pdf ↗

DiPS learns to optimize sketching policies for better recommendation quality.

problem Optimizing sketching policies for long-term user interest prediction in recommender systems.
method Differentiable policy for sketching that learns from training data.
result DiPS requires up to 50% fewer sketch items to achieve the same recommendation quality.

We improve prediction risk estimation for large datasets using sketching and ridge regression.

problem Estimating prediction risks for large datasets efficiently and accurately.
method Random matrix theory, generalized cross validation, sketched ridge regression ensembles, and ensemble trick.
result Consistent risk estimation and prediction intervals for large-scale datasets.

Improved sketching for logistic and 1\ell_1 regression with near-linear dimensions.

problem Efficiently approximate 1\ell_1 and logistic regression problems.
method New sketching techniques achieving near-linear dimensions for both problems.
result Achieved near-linear sketching dimensions for 1\ell_1 and logistic regression.

We consider statistical as well as algorithmic aspects of solving large-scale least-squares (LS) problems using randomized sketching algorithms. For a LS problem with input data (X,Y)Rn×p×Rn(X, Y) \in \mathbb{R}^{n \times p} \times \mathbb{R}^n, sketching algorithms use a sketching matrix, SRr×nS\in\mathbb{R}^{r \times n} with $r \…

2014-06-23abs ↗pdf ↗

New algorithm converts data into sub-gaussian designs efficiently.

problem Efficiently converting large datasets into sub-gaussian random designs for robust performance.
method Algorithmic Gaussianization through sketching and averaging, using LESS embeddings.
result Efficient data sketches nearly indistinguishable from sub-gaussian designs.

The paper sharpens the analysis of sketch-and-project methods using randomized singular value decomposition.

problem Improving convergence rates of sketch-and-project methods for solving linear systems and non-linear optimization problems.
method Developing a theoretical framework and new spectral bounds for the expected sketched projection matrix.
result The convergence rate improves linearly with sketch size and even faster with certain spectral decays.

The paper shows how sketching data can simplify regression inference even when errors are heteroskedastic.

problem Performing robust inference with heteroskedastic errors using sketched data.
method Using random projections to sketch data, the paper shows that sketched estimates behave as if errors are homoskedastic.
result Estimation by random sampling does not have the same property, and sketched estimates are asymptotically normal with homoskedastic variance.

The paper develops methods to estimate frequencies in large discrete data sets with improved coverage and robustness.

problem Estimating frequencies in large, discrete data sets with valid coverage and robustness.
method Conformal inference methods using discrete sketches, marginal coverage for queries, and novel conformal calibration.
result Improved empirical performance compared to existing methods in simulations and real data.

Sketching is more fundamental to human cognition than speech. Deep Neural Networks (DNNs) have achieved the state-of-the-art in speech-related tasks but have not made significant development in generating stroke-based sketches a.k.a sketches in vector format. Though there are Variational Auto Encoders (VAEs) for genera…

2019-04-07abs ↗pdf ↗

A fast sketching algorithm solves regularized least squares problems efficiently.

problem Solving large-scale optimization problems with convex or nonconvex regularization.
method Sketching for Regularized Optimization (SRO) algorithm that generates a sketch of the original data matrix and solves the sketched problem.
result General theoretical results for the approximation error between the original and sketched problems, including minimax rates for sparse signal estimation.

New sublinear sketches improve ANN and KDE for massive data streams.

problem Efficiently approximate nearest neighbors and kernel density estimation in large datasets.
method Developed sublinear space and query time algorithms for ANN and A-KDE in streaming and sliding-window models.
result Achieved near-optimal trade-offs between memory size and approximation error for ANN.

Structured high-cardinality data arises in many domains, and poses a major challenge for both modeling and inference. Graphical models are a popular approach to modeling structured data but they are unsuitable for high-cardinality variables. The count-min (CM) sketch is a popular approach to estimating probabilities in…

2016-02-09abs ↗pdf ↗

The immense amount of daily generated and communicated data presents unique challenges in their processing. Clustering, the grouping of data without the presence of ground-truth labels, is an important tool for drawing inferences from data. Subspace clustering (SC) is a relatively recent method that is able to successf…

2017-07-22abs ↗pdf ↗

New algorithm optimizes positions of CountSketch non-zero entries for better data compression.

problem Optimizing positions of CountSketch non-zero entries for better data compression.
method Learning algorithm that optimizes both values and positions of CountSketch non-zero entries.
result Improves accuracy for low rank approximation and other problems like k-means clustering.

Iterative Hessian sketch (IHS) is an effective sketching method for modeling large-scale data. It was originally proposed by Pilanci and Wainwright (2016; JMLR) based on randomized sketching matrices. However, it is computationally intensive due to the iterative sketch process. In this paper, we analyze the IHS algorit…

2019-02-20abs ↗pdf ↗

Matrix sketching is a recently developed data compression technique. An input matrix A is efficiently approximated with a smaller matrix B, so that B preserves most of the properties of A up to some guaranteed approximation ratio. In so doing numerical operations on big data sets become faster. Sketching algorithms gen…

2019-12-02abs ↗pdf ↗

Recent work has explored transforming data sets into smaller, approximate summaries in order to scale Bayesian inference. We examine a related problem in which the parameters of a Bayesian model are very large and expensive to store in memory, and propose more compact representations of parameter values that can be use…

2018-10-02abs ↗pdf ↗

New sketches for weighted p\ell_p sampling without replacement improve accuracy and efficiency.

problem Efficiently sampling weighted data with high accuracy and minimal redundancy.
method Design of novel composable sketches for WOR p\ell_p sampling, based on CountSketch.
result First to provide WOR sampling for p>1p>1 and signed updates.

We study sequential change-point detection procedures based on linear sketches of high-dimensional signal vectors using generalized likelihood ratio (GLR) statistics. The GLR statistics allow for an unknown post-change mean that represents an anomaly or novelty. We consider both fixed and time-varying projections, deri…

2015-05-25abs ↗pdf ↗

A new method reduces the bias in estimating inverse covariance matrices from sketches.

problem Reducing the bias in estimating inverse covariance matrices from sketches.
method Developed a framework for analyzing inversion bias and proposed a new sketching technique called LEverage Score Sparsified (LESS) embeddings.
result The new sketching technique reduces the inversion bias to O(1/d)O(1/\sqrt d) for m=O(d)m=O(d), significantly smaller than the Θ(1)Θ(1) approximation error.

Improved estimator for least squares using random projections achieves smaller error.

problem Improving the accuracy of least squares solutions for large-scale problems.
method James-Stein estimator applied to Gaussian sketching of least squares problems.
result Upper and lower bounds match when SNR is small and data matrix is well-conditioned.

New technique debiases distributed optimization, improving convergence rate.

problem Bias in local estimates limits effectiveness of distributed second order optimization.
method Surrogate sketching and scaled regularization to eliminate bias.
result The debiased local estimates lead to faster convergence in distributed optimization.

We present a mechanism to compute a sketch (succinct summary) of how a complex modular deep network processes its inputs. The sketch summarizes essential information about the inputs and outputs of the network and can be used to quickly identify key components and summary statistics of the inputs. Furthermore, the sket…

2019-05-29abs ↗pdf ↗

Improved ridge regression with Frequent Directions for large-scale tasks.

problem Improving performance of ridge regression for large-scale data.
method Combines Frequent Directions with iterative optimization schemes.
result Achieves high accuracy in estimating bias and variance for sketched ridge regression.

One-pass private sketch supports various machine learning tasks.

problem Efficiently supporting multiple machine learning tasks with differential privacy.
method Randomized contingency tables indexed with locality-sensitive hashing, constructed in one pass.
result Competitive error bounds for DP kernel density estimation, faster than existing methods.