abstract / bibtex / pdf / arXiv / code

Sparsity in Deep Neural Networks (DNNs) is studied extensively with the focus of maximizing prediction accuracy given an overall budget. Existing methods rely on uniform or heuristic non-uniform sparsity budgets which have sub-optimal layer-wise parameter allocation resulting in a) lower prediction accuracy or b) higher inference cost (FLOPs). This work proposes Soft Threshold Reparameterization (STR), a novel use of the soft-threshold operator on DNN weights. STR smoothly induces sparsity while learning pruning thresholds thereby obtaining a non-uniform sparsity budget. Our method achieves state-of-the-art accuracy for unstructured sparsity in CNNs (ResNet50 and MobileNetV1 on ImageNet-1K), and, additionally, learns non-uniform budgets that empirically reduce the FLOPs by up to 50%. Notably, STR boosts the accuracy over existing results by up to 10% in the ultra sparse (99%) regime and can also be used to induce low-rank (structured sparsity) in RNNs. In short, STR is a simple mechanism which learns effective sparsity budgets that contrast with popular heuristics.

@article{Kusupati20
  author    = {Kusupati, Aditya and Ramanujan, Vivek and
  Somani, Raghav and Wortsman, Mitchell and 
  Jain, Prateek and Kakade, Sham and Farhadi, Ali},
  title     = {Soft Threshold Weight Reparameterization 
  for Learnable Sparsity},
  booktitle = {arXiv preprint arXiv:2002.03231},
  year      = {2020},
}

abstract / bibtex / pdf / arXiv / code

Pooling operators are key components in most Convolutional Neural Networks (CNNs) as they serve to downsample images, aggregate feature information, and increase receptive field. However, standard pooling operators reduce the feature size gradually to avoid significant loss in information via gross aggregation. Consequently, CNN architectures tend to be deep, computationally expensive and challenging to deploy on RAM constrained devices. We introduce RNNPool, a novel pooling operator based on Recurrent Neural Networks (RNNs), that efficiently aggregate features over large patches of an image and rapidly downsamples its size. Our empirical evaluation indicates that an RNNPool layer(s) can effectively replace multiple blocks in a variety of architectures such as MobileNets (Sandler et al., 2018), DenseNet (Huang et al., 2017) and can be used for several vision tasks like image classification and face detection. That is, RNNPool can significantly decrease computational complexity and peak RAM usage for inference, while retaining comparable accuracy. Further, we use RNNPool to construct a novel real-time face detection method that achieves state-of-the-art MAP within computational budget afforded by a tiny Cortex M4 microcontroller with ~256 KB RAM.

@article{Saha20
  author    = {Saha, Oindrila and Kusupati, Aditya and 
  Simhadri, Harsha Vardhan and Varma, Manik and 
  Jain, Prateek},
  title     = {RNNPool: Efficient Non-linear Pooling 
  for RAM Constrained Inference},
  booktitle = {arXiv preprint arXiv:2002.11921},
  year      = {2020},
}

abstract / bibtex / pdf / reviews / arXiv / code / XML Repository

This paper introduces a new learning paradigm called eXtreme Regression (XR) whose objective is to accurately predict the numerical degrees of relevance of an extremely large number of labels to a data point. XR can provide elegant solutions to many large-scale ranking and recommendation applications including Dynamic Search Advertising (DSA). XR can learn more accurate models than the recently popular extreme classifiers which incorrectly assume strictly binary-valued label relevances. Traditional regression metrics which sum the errors over all the labels are unsuitable for XR problems since they could give extremely loose bounds for the label ranking quality. Also, the existing regression algorithms won't efficiently scale to millions of labels. This paper addresses these limitations through: (1) new evaluation metrics for XR which sum only the k largest regression errors; (2) a new algorithm called XReg which decomposes XR task into a hierarchy of much smaller regression problems thus leading to highly efficient training and prediction. This paper also introduces a (3) new labelwise prediction algorithm in XReg useful for DSA and other recommendation tasks.
Experiments on benchmark datasets demonstrated that XReg can outperform the state-of-the-art extreme classifiers as well as large-scale regressors and rankers by up to 50% reduction in the new XR error metric, and up to 2% and 2.4% improvements in terms of the propensity-scored precision metric used in extreme classification and the click-through rate metric used in DSA respectively. Deployment of XReg on DSA in Bing resulted in a relative gain of 58% in revenue and 27% in query coverage. XReg's source code can be downloaded from http://manikvarma.org/code/XReg/download.html.

@InProceedings{Prabhu20,
  author    = {Prabhu, Prabhu and Kusupati, Aditya and 
  Gupta, Nilesh and Varma, Manik},
  title     = {Extreme Regression for Dynamic 
  Search Advertising},
  booktitle = {Proceedings of the ACM International 
  Conference on Web Search and Data Mining},
  month     = {February},
  year      = {2020},
}

abstract / bibtex / pdf / reviews / arXiv / code / poster / dataset / blog

Edge sensing with micro-power pulse-Doppler radars is an emergent domain in monitoring and surveillance with several smart city applications. Existing solutions for the clutter versus multi-source radar classification task are limited in terms of either accuracy or efficiency, and in some cases, struggle with a trade-off between false alarms and recall of sources. We find that this problem can be resolved by learning the classifier across multiple time-scales. We propose a multi-scale, cascaded recurrent neural network architecture, MSC-RNN, comprised of an efficient multi-instance learning (MIL) Recurrent Neural Network (RNN) for clutter discrimination at a lower tier, and a more complex RNN classifier for source classification at the upper tier. By controlling the invocation of the upper RNN with the help of the lower tier conditionally, MSC-RNN achieves an overall accuracy of 0.972. Our approach holistically improves the accuracy and per-class recalls over machine learning models suitable for radar inferencing. Notably, we outperform cross-domain handcrafted feature engineering with purely time-domain deep feature learning, while also being up to ~3x more efficient than a competitive solution.

@InProceedings{Roy19,
  author    = {Roy, Dhrubojyoti and Srivastava, Sangeeta 
  and Kusupati, Aditya and Jain, Pranshu and 
  Varma, Manik and Arora, Anish},
  title     = {One Size Does Not Fit All: 
  Multi-Scale, Cascaded RNNs for 
  Radar Classification},
  booktitle = {Proceedings of the ACM International 
  Conference on Systems for Energy-Efficient 
  Buildings, Cities, and Transportation},
  month     = {November},
  year      = {2019},
}

abstract / bibtex / pdf / reviews / arXiv / code / video / poster / blog

This paper develops the FastRNN and FastGRNN algorithms to address the twin RNN limitations of inaccurate training and inefficient prediction. Previous approaches have improved accuracy at the expense of prediction costs making them infeasible for resource-constrained and real-time applications. Unitary RNNs have increased accuracy somewhat by restricting the range of the state transition matrix's singular values but have also increased the model size as they require a larger number of hidden units to make up for the loss in expressive power. Gated RNNs have obtained state-of-the-art accuracies by adding extra parameters thereby resulting in even larger models. FastRNN addresses these limitations by adding a residual connection that does not constrain the range of the singular values explicitly and has only two extra scalar parameters. FastGRNN then extends the residual connection to a gate by reusing the RNN matrices to match state-of-the-art gated RNN accuracies but with a 2-4x smaller model. Enforcing FastGRNN's matrices to be low-rank, sparse and quantized resulted in accurate models that could be up to 35x smaller than leading gated and unitary RNNs. This allowed FastGRNN to accurately recognize the "Hey Cortana" wakeword with a 1 KB model and to be deployed on severely resource-constrained IoT microcontrollers too tiny to store other RNN models. FastGRNN's code is available at https://github.com/Microsoft/EdgeML/.

@InProceedings{Kusupati18,
  author    = {Kusupati, Aditya and Singh, Manish and 
  Bhatia, Kush and Kumar, Ashish and 
  Jain, Prateek and Varma, Manik},
  title     = {{FastGRNN}: A Fast, Accurate, 
  Stable and Tiny Kilobyte Sized 
  Gated Recurrent Neural Network.},
  booktitle = {Advances in 
  Neural Information Processing Systems},
  month     = {December},
  year      = {2018},
}

abstract / bibtex / pdf

We demonstrate Multi-Scale, Cascaded RNN (MSC-RNN), an energy-efficient recurrent neural network for real-time micro-power radar classification. Its two-tier architecture is jointly trained to reject clutter and discriminate displacing sources at different time-scales, with a lighter lower tier running continuously and a heavier upper tier invoked infrequently on an on-demand basis. It offers for single microcontroller devices a better trade-off in accuracy and efficiency, as well as in clutter suppression and detectability, over competitive shallow and deep alternatives.

@InProceedings{Roy19-demo,
  author    = {Roy, Dhrubojyoti and Srivastava, Sangeeta 
  and Jain, Pranshu and Kusupati, Aditya and 
  Varma, Manik and Arora, Anish},
  title     = {Lightweight, Deep RNNs 
  for Radar Classification},
  booktitle = {Proceedings of the ACM International 
  Conference on Systems for Energy-Efficient 
  Buildings, Cities, and Transportation},
  month     = {November},
  year      = {2019},
}

abstract / bibtex / pdf

The project aims at creating a efficient spatial embeddings for entities and types which would be useful for various downstream tasks such as Knowledge Base Completion, Fine-Type Tagging and Question Answering.

@article{Kusupati17,
  author = {Dhoot, Anand and Kusupati, Aditya 
  and Chakrabarti, Soumen},
  title = {Efficient Spatial Representation 
  for Entity-Typing},
  booktitle = {Undergraduate Thesis, CSE IIT Bombay},
  year = {2016-17},
}

abstract / bibtex

Open source repository for all the research outputs on resource efficient Machine Learning from Microsoft Research India. It contains scalable and multi-framework compatible implementations of Bonsai, ProtoNN, FastCells, EMI-RNN, ShaRNN, a tool named SeeDot for fixed-point compilation of ML models along with applications such as on-device Keyword spotting and Gesturepod.
EdgeML is under MIT license and is open to contributions and suggestions. Please cite the software if you happen to use EdgeML in your research or otherwise (use the latest bibtex from the repository in case this gets outdated)

@misc{edgeml03,
    author = {{Dennis, Don Kurian and Gaurkar, Yash and Gopinath, Sridhar and 
    Gupta, Chirag and Jain, Moksh and Kumar, Ashish and Kusupati, Aditya and 
    Lovett, Chris and Patil, Shishir Girish and Simhadri, Harsha Vardhan}},
    title = {{EdgeML: Machine Learning for resource-constrained edge devices}},
    url = {https://github.com/Microsoft/EdgeML},
    version = {0.3},
}