82 research outputs found
End-to-end Feature Selection Approach for Learning Skinny Trees
Joint feature selection and tree ensemble learning is a challenging task.
Popular tree ensemble toolkits e.g., Gradient Boosted Trees and Random Forests
support feature selection post-training based on feature importances, which are
known to be misleading, and can significantly hurt performance. We propose
Skinny Trees: a toolkit for feature selection in tree ensembles, such that
feature selection and tree ensemble learning occurs simultaneously. It is based
on an end-to-end optimization approach that considers feature selection in
differentiable trees with Group regularization. We optimize
with a first-order proximal method and present convergence guarantees for a
non-convex and non-smooth objective. Interestingly, dense-to-sparse
regularization scheduling can lead to more expressive and sparser tree
ensembles than vanilla proximal method. On 15 synthetic and real-world
datasets, Skinny Trees can achieve - feature
compression rates, leading up to faster inference over dense trees,
without any loss in performance. Skinny Trees lead to superior feature
selection than many existing toolkits e.g., in terms of AUC performance for
feature budget, Skinny Trees outperforms LightGBM by (up to
), and Random Forests by (up to ).Comment: Preprin
Learning to Prune Deep Neural Networks via Layer-wise Optimal Brain Surgeon
How to develop slim and accurate deep neural networks has become crucial for
real- world applications, especially for those employed in embedded systems.
Though previous work along this research line has shown some promising results,
most existing methods either fail to significantly compress a well-trained deep
network or require a heavy retraining process for the pruned deep network to
re-boost its prediction performance. In this paper, we propose a new layer-wise
pruning method for deep neural networks. In our proposed method, parameters of
each individual layer are pruned independently based on second order
derivatives of a layer-wise error function with respect to the corresponding
parameters. We prove that the final prediction performance drop after pruning
is bounded by a linear combination of the reconstructed errors caused at each
layer. Therefore, there is a guarantee that one only needs to perform a light
retraining process on the pruned network to resume its original prediction
performance. We conduct extensive experiments on benchmark datasets to
demonstrate the effectiveness of our pruning method compared with several
state-of-the-art baseline methods
SCANN: Synthesis of Compact and Accurate Neural Networks
Deep neural networks (DNNs) have become the driving force behind recent
artificial intelligence (AI) research. An important problem with implementing a
neural network is the design of its architecture. Typically, such an
architecture is obtained manually by exploring its hyperparameter space and
kept fixed during training. This approach is time-consuming and inefficient.
Another issue is that modern neural networks often contain millions of
parameters, whereas many applications and devices require small inference
models. However, efforts to migrate DNNs to such devices typically entail a
significant loss of classification accuracy. To address these challenges, we
propose a two-step neural network synthesis methodology, called DR+SCANN, that
combines two complementary approaches to design compact and accurate DNNs. At
the core of our framework is the SCANN methodology that uses three basic
architecture-changing operations, namely connection growth, neuron growth, and
connection pruning, to synthesize feed-forward architectures with arbitrary
structure. SCANN encapsulates three synthesis methodologies that apply a
repeated grow-and-prune paradigm to three architectural starting points.
DR+SCANN combines the SCANN methodology with dataset dimensionality reduction
to alleviate the curse of dimensionality. We demonstrate the efficacy of SCANN
and DR+SCANN on various image and non-image datasets. We evaluate SCANN on
MNIST and ImageNet benchmarks. In addition, we also evaluate the efficacy of
using dimensionality reduction alongside SCANN (DR+SCANN) on nine small to
medium-size datasets. We also show that our synthesis methodology yields neural
networks that are much better at navigating the accuracy vs. energy efficiency
space. This would enable neural network-based inference even on
Internet-of-Things sensors.Comment: 13 pages, 8 figure
Attributing Learned Concepts in Neural Networks to Training Data
By now there is substantial evidence that deep learning models learn certain
human-interpretable features as part of their internal representations of data.
As having the right (or wrong) concepts is critical to trustworthy machine
learning systems, it is natural to ask which inputs from the model's original
training set were most important for learning a concept at a given layer. To
answer this, we combine data attribution methods with methods for probing the
concepts learned by a model. Training network and probe ensembles for two
concept datasets on a range of network layers, we use the recently developed
TRAK method for large-scale data attribution. We find some evidence for
convergence, where removing the 10,000 top attributing images for a concept and
retraining the model does not change the location of the concept in the network
nor the probing sparsity of the concept. This suggests that rather than being
highly dependent on a few specific examples, the features that inform the
development of a concept are spread in a more diffuse manner across its
exemplars, implying robustness in concept formation
- …