Search Results for author: James Sharpnack

Found 18 papers, 6 papers with code

RLSbench: Domain Adaptation Under Relaxed Label Shift

1 code implementation6 Feb 2023 Saurabh Garg, Nick Erickson, James Sharpnack, Alex Smola, Sivaraman Balakrishnan, Zachary C. Lipton

Despite the emergence of principled methods for domain adaptation under label shift, their sensitivity to shifts in class conditional distributions is precariously under explored.

Domain Adaptation

Syndicated Bandits: A Framework for Auto Tuning Hyper-parameters in Contextual Bandit Algorithms

no code implementations5 Jun 2021 Qin Ding, Yue Kang, Yi-Wei Liu, Thomas C. M. Lee, Cho-Jui Hsieh, James Sharpnack

To tackle this problem, we first propose a two-layer bandit structure for auto tuning the exploration parameter and further generalize it to the Syndicated Bandits framework which can learn multiple hyper-parameters dynamically in contextual bandit environment.

Recommendation Systems

Robust Stochastic Linear Contextual Bandits Under Adversarial Attacks

no code implementations5 Jun 2021 Qin Ding, Cho-Jui Hsieh, James Sharpnack

We provide theoretical guarantees for our proposed algorithm and show by experiments that our proposed algorithm improves the robustness against various kinds of popular attacks.

Multi-Armed Bandits Recommendation Systems

An Efficient Algorithm For Generalized Linear Bandit: Online Stochastic Gradient Descent and Thompson Sampling

no code implementations7 Jun 2020 Qin Ding, Cho-Jui Hsieh, James Sharpnack

A natural way to resolve this problem is to apply online stochastic gradient descent (SGD) so that the per-step time and memory complexity can be reduced to constant with respect to $t$, but a contextual bandit policy based on online SGD updates that balances exploration and exploitation has remained elusive.

Thompson Sampling

Multiscale Non-stationary Stochastic Bandits

no code implementations13 Feb 2020 Qin Ding, Cho-Jui Hsieh, James Sharpnack

Classic contextual bandit algorithms for linear models, such as LinUCB, assume that the reward distribution for an arm is modeled by a stationary linear regression.

regression

Unsupervised Object Segmentation with Explicit Localization Module

no code implementations21 Nov 2019 Weitang Liu, Lifeng Wei, James Sharpnack, John D. Owens

In this paper, we propose a novel architecture that iteratively discovers and segments out the objects of a scene based on the image reconstruction quality.

Image Reconstruction Object +2

SSE-PT: Sequential Recommendation Via Personalized Transformer

2 code implementations25 Sep 2019 Liwei Wu, Shuqing Li, Cho-Jui Hsieh, James Sharpnack

Recent advances in deep learning, especially the discovery of various attention mechanisms and newer architectures in addition to widely used RNN and CNN in natural language processing, have allowed for better use of the temporal ordering of items that each user has engaged with.

 Ranked #1 on Recommendation Systems on MovieLens 1M (nDCG@10 metric)

Sequential Recommendation

Temporal Collaborative Ranking Via Personalized Transformer

3 code implementations15 Aug 2019 Liwei Wu, Shuqing Li, Cho-Jui Hsieh, James Sharpnack

Recent advances in deep learning, especially the discovery of various attention mechanisms and newer architectures in addition to widely used RNN and CNN in natural language processing, have allowed us to make better use of the temporal ordering of items that each user has engaged with.

Collaborative Ranking

Graph DNA: Deep Neighborhood Aware Graph Encoding for Collaborative Filtering

no code implementations29 May 2019 Liwei Wu, Hsiang-Fu Yu, Nikhil Rao, James Sharpnack, Cho-Jui Hsieh

In this paper, we propose using Graph DNA, a novel Deep Neighborhood Aware graph encoding algorithm, for exploiting deeper neighborhood information.

Collaborative Filtering Recommendation Systems

Stochastic Shared Embeddings: Data-driven Regularization of Embedding Layers

3 code implementations NeurIPS 2019 Liwei Wu, Shuqing Li, Cho-Jui Hsieh, James Sharpnack

We find that when used along with widely-used regularization methods such as weight decay and dropout, our proposed SSE can further reduce overfitting, which often leads to more favorable generalization results.

Knowledge Graphs Recommendation Systems

On $L_2$-consistency of nearest neighbor matching

no code implementations6 Feb 2019 James Sharpnack

Biased sampling and missing data complicates statistical problems ranging from causal inference to reinforcement learning.

Causal Inference Domain Adaptation +3

Distributed Cartesian Power Graph Segmentation for Graphon Estimation

no code implementations25 May 2018 Shitong Wei, Oscar Hernan Madrid-Padilla, James Sharpnack

We study an extention of total variation denoising over images to over Cartesian power graphs and its applications to estimating non-parametric network models.

Denoising Graphon Estimation

SQL-Rank: A Listwise Approach to Collaborative Ranking

1 code implementation ICML 2018 Liwei Wu, Cho-Jui Hsieh, James Sharpnack

In this paper, we propose a listwise approach for constructing user-specific rankings in recommendation systems in a collaborative fashion.

Collaborative Ranking Recommendation Systems

Estimating Graphlet Statistics via Lifting

1 code implementation23 Feb 2018 Kirill Paramonov, Dmitry Shemetov, James Sharpnack

Exploratory analysis over network data is often limited by the ability to efficiently calculate graph statistics, which can provide a model-free understanding of the macroscopic properties of a network.

Trend Filtering on Graphs

no code implementations28 Oct 2014 Yu-Xiang Wang, James Sharpnack, Alex Smola, Ryan J. Tibshirani

We introduce a family of adaptive estimators on graphs, based on penalizing the $\ell_1$ norm of discrete graph differences.

regression

Near-optimal Anomaly Detection in Graphs using Lovasz Extended Scan Statistic

no code implementations NeurIPS 2013 James Sharpnack, Akshay Krishnamurthy, Aarti Singh

The detection of anomalous activity in graphs is a statistical problem that arises in many applications, such as network surveillance, disease outbreak detection, and activity monitoring in social networks.

Anomaly Detection

Recovering Graph-Structured Activations using Adaptive Compressive Measurements

no code implementations1 May 2013 Akshay Krishnamurthy, James Sharpnack, Aarti Singh

We study the localization of a cluster of activated vertices in a graph, from adaptively designed compressive measurements.

Identifying graph-structured activation patterns in networks

no code implementations NeurIPS 2010 James Sharpnack, Aarti Singh

We consider the problem of identifying an activation pattern in a complex, large-scale network that is embedded in very noisy measurements.

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