@inproceedings{18118,
  abstract     = {We introduce a new framework for studying meta-learning methods using PAC-Bayesian theory. Its main advantage over previous work is that it allows for more flexibility in how the transfer of knowledge between tasks is realized. For previous approaches, this could only happen indirectly, by means of learning prior distributions over models. In contrast, the new generalization bounds that we prove express the process of meta-learning much more directly as learning the learning algorithm that should be used for future tasks. The flexibility of our framework makes it suitable to analyze a wide range of meta-learning mechanisms and even design new mechanisms. Other than our theoretical contributions we also show empirically that our framework improves the prediction quality in practical meta-learning mechanisms.},
  author       = {Zakerinia, Hossein and Behjati, Amin and Lampert, Christoph},
  booktitle    = {Proceedings of the 41st International Conference on Machine Learning},
  issn         = {2640-3498},
  location     = {Vienna, Austria},
  pages        = {58122--58139},
  publisher    = {ML Research Press},
  title        = {{More flexible PAC-Bayesian meta-learning by learning learning algorithms}},
  volume       = {235},
  year         = {2024},
}

@article{18856,
  abstract     = {This research is aimed to solve the tweet/user geolocation prediction task and provide a flexible methodology for the geo-tagging of textual big data. The suggested approach implements neural networks for natural language processing (NLP) to estimate the location as coordinate pairs (longitude, latitude) and two-dimensional Gaussian Mixture Models (GMMs). The scope of proposed models has been finetuned on a Twitter dataset using pretrained Bidirectional Encoder Representations from Transformers (BERT) as base models. Performance metrics show a median error of fewer than 30 km on a worldwide-level, and fewer than 15 km on the US-level datasets for the models trained and evaluated on text features of tweets' content and metadata context. Our source code and data are available at https://github.com/K4TEL/geo-twitter.git.},
  author       = {Lutsai, Kateryna and Lampert, Christoph},
  issn         = {1948-660X},
  journal      = {Journal of Spatial Information Science},
  number       = {29},
  pages        = {69--99},
  publisher    = {University of Maine},
  title        = {{Predicting the geolocation of tweets using transformer models on customized data}},
  doi          = {10.5311/JOSIS.2024.29.295},
  year         = {2024},
}

@inproceedings{18875,
  abstract     = {Current state-of-the-art methods for differentially private model training are based on matrix factorization techniques. However, these methods suffer from high computational overhead because they require numerically solving a demanding optimization problem to determine an approximately optimal factorization prior to the actual model training. In this work, we present a new matrix factorization approach, BSR, which overcomes this computational bottleneck. By exploiting properties of the standard matrix square root, BSR allows to efficiently handle also large-scale problems. For the key scenario of stochastic gradient descent with momentum and weight decay, we even derive analytical expressions for BSR that render the computational overhead negligible. We prove bounds on the approximation quality that hold both in the centralized and in the federated learning setting. Our numerical experiments demonstrate that models trained using BSR perform on par with the best existing methods, while completely avoiding their computational overhead.},
  author       = {Kalinin, Nikita and Lampert, Christoph},
  booktitle    = {38th Annual Conference on Neural Information Processing Systems},
  issn         = {1049-5258},
  location     = {Vancouver, Canada},
  publisher    = {Neural Information Processing Systems Foundation},
  title        = {{Banded square root matrix factorization for differentially private model training}},
  volume       = {37},
  year         = {2024},
}

@inproceedings{18891,
  abstract     = {Deep neural networks (DNNs) exhibit a surprising structure in their final layer
known as neural collapse (NC), and a growing body of works has currently investigated the propagation of neural collapse to earlier layers of DNNs – a phenomenon
called deep neural collapse (DNC). However, existing theoretical results are restricted to special cases: linear models, only two layers or binary classification.
In contrast, we focus on non-linear models of arbitrary depth in multi-class classification and reveal a surprising qualitative shift. As soon as we go beyond two
layers or two classes, DNC stops being optimal for the deep unconstrained features
model (DUFM) – the standard theoretical framework for the analysis of collapse.
The main culprit is a low-rank bias of multi-layer regularization schemes: this bias
leads to optimal solutions of even lower rank than the neural collapse. We support
our theoretical findings with experiments on both DUFM and real data, which show
the emergence of the low-rank structure in the solution found by gradient descent.},
  author       = {Súkeník, Peter and Lampert, Christoph and Mondelli, Marco},
  booktitle    = {38th Annual Conference on Neural Information Processing Systems},
  location     = {Vancouver, Canada},
  publisher    = {Neural Information Processing Systems Foundation},
  title        = {{Neural collapse versus low-rank bias: Is deep neural collapse really optimal?}},
  volume       = {37},
  year         = {2024},
}

@unpublished{19063,
  abstract     = {Instruction-tuned Large Language Models (LLMs) show impressive results in numerous practical applications, but they lack essential safety features that are common in other areas of computer science, particularly an explicit separation of instructions and data. This makes them vulnerable to manipulations such as indirect prompt injections and generally unsuitable for safety-critical tasks. Surprisingly, there is currently no established definition or benchmark to quantify this phenomenon. In this work, we close this gap by introducing a formal measure for instruction-data separation and an empirical variant that is calculable from a model's outputs. We also present a new dataset, SEP, that allows estimating the measure for real-world models. Our results on various LLMs show that the problem of instruction-data separation is real: all models fail to achieve high separation, and canonical mitigation techniques, such as prompt engineering and fine-tuning, either fail to substantially improve separation or reduce model utility. The source code and SEP dataset are openly accessible at https://github.com/egozverev/Shold-It-Be-Executed-Or-Processed.
},
  author       = {Zverev, Egor and Abdelnabi, Sahar and Tabesh, Soroush and Fritz, Mario and Lampert, Christoph},
  booktitle    = {arXiv},
  title        = {{Can LLMs separate instructions from data? And what do we even mean by that?}},
  doi          = {10.48550/arXiv.2403.06833},
  year         = {2024},
}

@article{19408,
  abstract     = {Continual learning is a subfield of machine learning, which aims to allow machine learning models to continuously learn on new data, by accumulating knowledge without forgetting what was learned in the past. In this work, we take a step back, and ask: "Why should one care about continual learning in the first place?". We set the stage by examining recent continual learning papers published at four major machine learning conferences, and show that memory-constrained settings dominate the field. Then, we discuss five open problems in machine learning, and even though they might seem unrelated to continual learning at first sight, we show that continual learning will inevitably be part of their solution. These problems are model editing, personalization and specialization, on-device learning, faster (re-)training and reinforcement learning. Finally, by comparing the desiderata from these unsolved problems and the current assumptions in continual learning, we highlight and discuss four future directions for continual learning research. We hope that this work offers an interesting perspective on the future of continual learning, while displaying its potential value and the paths we have to pursue in order to make it successful. This work is the result of the many discussions the authors had at the Dagstuhl seminar on Deep Continual Learning, in March 2023.},
  author       = {Verwimp, Eli and Aljundi, Rahaf and Ben-David, Shai and Bethge, Matthias and Cossu, Andrea and Gepperth, Alexander and Hayes, Tyler L. and Hüllermeier, Eyke and Kanan, Christopher and Kudithipudi, Dhireesha and Lampert, Christoph and Mundt, Martin and Pascanu, Razvan and Popescu, Adrian and Tolias, Andreas S. and Van De Weijer, Joost and Liu, Bing and Lomonaco, Vincenzo and Tuytelaars, Tinne and Van De Ven, Gido M.},
  issn         = {2835-8856},
  journal      = {Transactions on Machine Learning Research},
  publisher    = {Transactions on Machine Learning Research},
  title        = {{Continual learning: Applications and the road forward}},
  volume       = {2024},
  year         = {2024},
}

@inproceedings{17093,
  abstract     = {Federated Learning (FL) enables large-scale distributed training of machine learning models, while still allowing individual nodes to maintain data locally. However, executing FL at scale comes with inherent practical challenges: 1) heterogeneity of the local node data distributions, 2) heterogeneity of node computational speeds (asynchrony), but also 3) constraints in the amount of communication between the clients and the server. In this work, we present the first variant of the classic federated averaging (FedAvg) algorithm which, at the same time, supports data heterogeneity, partial client asynchrony, and communication compression. Our algorithm comes with a novel, rigorous analysis showing that, in spite of these system relaxations, it can provide similar convergence to FedAvg in interesting parameter regimes. Experimental results in the rigorous LEAF benchmark on setups of up to 300 nodes show that our algorithm ensures fast convergence for standard federated tasks, improving upon prior quantized and asynchronous approaches.},
  author       = {Zakerinia, Hossein and Talaei, Shayan and Nadiradze, Giorgi and Alistarh, Dan-Adrian},
  booktitle    = {Proceedings of the 27th International Conference on Artificial Intelligence and Statistics},
  issn         = {2640-3498},
  location     = {Valencia, Spain},
  pages        = {3448--3456},
  publisher    = {ML Research Press},
  title        = {{Communication-efficient federated learning with data and client heterogeneity}},
  volume       = {238},
  year         = {2024},
}

@inproceedings{17411,
  abstract     = {We present PeFLL, a new personalized federated learning algorithm that improves
over the state-of-the-art in three aspects: 1) it produces more accurate models,
especially in the low-data regime, and not only for clients present during its
training phase, but also for any that may emerge in the future; 2) it reduces the
amount of on-client computation and client-server communication by providing
future clients with ready-to-use personalized models that require no additional
finetuning or optimization; 3) it comes with theoretical guarantees that establish
generalization from the observed clients to future ones.
At the core of PeFLL lies a learning-to-learn approach that jointly trains an
embedding network and a hypernetwork. The embedding network is used to
represent clients in a latent descriptor space in a way that reflects their similarity
to each other. The hypernetwork takes as input such descriptors and outputs the
parameters of fully personalized client models. In combination, both networks
constitute a learning algorithm that achieves state-of-the-art performance in several
personalized federated learning benchmarks},
  author       = {Scott, Jonathan A and Zakerinia, Hossein and Lampert, Christoph},
  booktitle    = {12th International Conference on Learning Representations},
  location     = {Vienna, Austria},
  publisher    = {OpenReview},
  title        = {{PEFLL: Personalized federated learning by learning to learn}},
  year         = {2024},
}

@inproceedings{18120,
  abstract     = {In practice, training using federated learning can be orders of magnitude slower than standard centralized training. This severely limits the amount of experimentation and tuning that can be done, making it challenging to obtain good performance on a given task. Server-side proxy data can be used to run training simulations, for instance for hyperparameter tuning. This can greatly speed up the training pipeline by reducing the number of tuning runs to be performed overall on the true clients. However, it is challenging to ensure that these simulations accurately reflect the dynamics of the real federated training. In particular, the proxy data used for simulations often comes as a single centralized dataset without a partition into distinct clients, and partitioning this data in a naive way can lead to simulations that poorly reflect real federated training. In this paper we address the challenge of how to partition centralized data in a way that reflects the statistical heterogeneity of the true federated clients. We propose a fully federated, theoretically justified, algorithm that efficiently learns the distribution of the true clients and observe improved server-side simulations when using the inferred distribution to create simulated clients from the centralized data.},
  author       = {Scott, Jonathan A and Cahill, Áine},
  booktitle    = {Proceedings of the 41st International Conference on Machine Learning},
  issn         = {2640-3498},
  location     = {Vienna, Austria},
  pages        = {44012--44037},
  publisher    = {ML Research Press},
  title        = {{Improved modelling of federated datasets using mixtures-of-Dirichlet-multinomials}},
  volume       = {235},
  year         = {2024},
}

@inproceedings{17426,
  abstract     = {The robustness of neural networks against input perturbations with bounded
magnitude represents a serious concern in the deployment of deep learning
models in safety-critical systems. Recently, the scientific community has
focused on enhancing certifiable robustness guarantees by crafting 1-Lipschitz
neural networks that leverage Lipschitz bounded dense and convolutional layers.
Although different methods have been proposed in the literature to achieve this
goal, understanding the performance of such methods is not straightforward,
since different metrics can be relevant (e.g., training time, memory usage,
accuracy, certifiable robustness) for different applications. For this reason,
this work provides a thorough theoretical and empirical comparison between
methods by evaluating them in terms of memory usage, speed, and certifiable
robust accuracy. The paper also provides some guidelines and recommendations to
support the user in selecting the methods that work best depending on the
available resources. We provide code at
https://github.com/berndprach/1LipschitzLayersCompared.},
  author       = {Prach, Bernd and Brau, Fabio and Buttazzo, Giorgio and Lampert, Christoph},
  booktitle    = {Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition},
  location     = {Seattle, WA, United States},
  pages        = {24574--24583},
  publisher    = {Computer Vision Foundation},
  title        = {{1-Lipschitz layers compared: Memory, speed, and certifiable robustness}},
  doi          = {10.1109/CVPR52733.2024.02320},
  year         = {2024},
}

@unpublished{18874,
  abstract     = {Despite extensive research since the community learned about adversarial
examples 10 years ago, we still do not know how to train high-accuracy
classifiers that are guaranteed to be robust to small perturbations of their
inputs. Previous works often argued that this might be because no classifier
exists that is robust and accurate at the same time. However, in computer
vision this assumption does not match reality where humans are usually accurate
and robust on most tasks of interest. We offer an alternative explanation and
show that in certain settings robust generalization is only possible with
unrealistically large amounts of data. More precisely we find a setting where a
robust classifier exists, it is easy to learn an accurate classifier, yet it
requires an exponential amount of data to learn a robust classifier. Based on
this theoretical result, we explore how well robust classifiers generalize on
datasets such as CIFAR-10. We come to the conclusion that on this datasets, the
limitation of current robust models also lies in the generalization, and that
they require a lot of data to do well on the test set. We also show that the
problem is not in the expressiveness or generalization capabilities of current
architectures, and that there are low magnitude features in the data which are
useful for non-robust generalization but are not available for robust
classifiers.},
  author       = {Prach, Bernd and Lampert, Christoph},
  booktitle    = {arXiv},
  title        = {{Intriguing properties of robust classification}},
  doi          = {10.48550/arXiv.2412.04245},
  year         = {2024},
}

@article{14320,
  abstract     = {The development of two-dimensional materials has resulted in a diverse range of novel, high-quality compounds with increasing complexity. A key requirement for a comprehensive quantitative theory is the accurate determination of these materials' band structure parameters. However, this task is challenging due to the intricate band structures and the indirect nature of experimental probes. In this work, we introduce a general framework to derive band structure parameters from experimental data using deep neural networks. We applied our method to the penetration field capacitance measurement of trilayer graphene, an effective probe of its density of states. First, we demonstrate that a trained deep network gives accurate predictions for the penetration field capacitance as a function of tight-binding parameters. Next, we use the fast and accurate predictions from the trained network to automatically determine tight-binding parameters directly from experimental data, with extracted parameters being in a good agreement with values in the literature. We conclude by discussing potential applications of our method to other materials and experimental techniques beyond penetration field capacitance.},
  author       = {Henderson, Paul M and Ghazaryan, Areg and Zibrov, Alexander A. and Young, Andrea F. and Serbyn, Maksym},
  issn         = {2469-9969},
  journal      = {Physical Review B},
  number       = {12},
  publisher    = {American Physical Society},
  title        = {{Deep learning extraction of band structure parameters from density of states: A case study on trilayer graphene}},
  doi          = {10.1103/physrevb.108.125411},
  volume       = {108},
  year         = {2023},
}

@inproceedings{14410,
  abstract     = {This paper focuses on the implementation details of the baseline methods and a recent lightweight conditional model extrapolation algorithm LIMES [5] for streaming data under class-prior shift. LIMES achieves superior performance over the baseline methods, especially concerning the minimum-across-day accuracy, which is important for the users of the system. In this work, the key measures to facilitate reproducibility and enhance the credibility of the results are described.},
  author       = {Tomaszewska, Paulina and Lampert, Christoph},
  booktitle    = {International Workshop on Reproducible Research in Pattern Recognition},
  isbn         = {9783031407727},
  issn         = {1611-3349},
  location     = {Montreal, Canada},
  pages        = {67--73},
  publisher    = {Springer Nature},
  title        = {{On the implementation of baselines and lightweight conditional model extrapolation (LIMES) under class-prior shift}},
  doi          = {10.1007/978-3-031-40773-4_6},
  volume       = {14068},
  year         = {2023},
}

@article{14446,
  abstract     = {Recent work has paid close attention to the first principle of Granger causality, according to which cause precedes effect. In this context, the question may arise whether the detected direction of causality also reverses after the time reversal of unidirectionally coupled data. Recently, it has been shown that for unidirectionally causally connected autoregressive (AR) processes X → Y, after time reversal of data, the opposite causal direction Y → X is indeed detected, although typically as part of the bidirectional X↔ Y link. As we argue here, the answer is different when the measured data are not from AR processes but from linked deterministic systems. When the goal is the usual forward data analysis, cross-mapping-like approaches correctly detect X → Y, while Granger causality-like approaches, which should not be used for deterministic time series, detect causal independence X → Y. The results of backward causal analysis depend on the predictability of the reversed data. Unlike AR processes, observables from deterministic dynamical systems, even complex nonlinear ones, can be predicted well forward, while backward predictions can be difficult (notably when the time reversal of a function leads to one-to-many relations). To address this problem, we propose an approach based on models that provide multiple candidate predictions for the target, combined with a loss function that consideres only the best candidate. The resulting good forward and backward predictability supports the view that unidirectionally causally linked deterministic dynamical systems X → Y can be expected to detect the same link both before and after time reversal.},
  author       = {Jakubík, Jozef and Bui Thi Mai, Phuong and Chvosteková, Martina and Krakovská, Anna},
  issn         = {1335-8871},
  journal      = {Measurement Science Review},
  number       = {4},
  pages        = {175--183},
  publisher    = {Sciendo},
  title        = {{Against the flow of time with multi-output models}},
  doi          = {10.2478/msr-2023-0023},
  volume       = {23},
  year         = {2023},
}

@inproceedings{12660,
  abstract     = {We present Cross-Client Label Propagation(XCLP), a new method for transductive federated learning. XCLP estimates a data graph jointly from the data of multiple clients and computes labels for the unlabeled data by propagating label information across the graph. To avoid clients having to share their data with anyone, XCLP employs two cryptographically secure protocols: secure Hamming distance computation and secure summation. We demonstrate two distinct applications of XCLP within federated learning. In the first, we use it in a one-shot way to predict labels for unseen test points. In the second, we use it to repeatedly pseudo-label unlabeled training data in a federated semi-supervised setting. Experiments on both real federated and standard benchmark datasets show that in both applications XCLP achieves higher classification accuracy than alternative approaches.},
  author       = {Scott, Jonathan A and Yeo, Michelle X and Lampert, Christoph},
  booktitle    = {Transactions in Machine Learning},
  issn         = {2835-8856},
  publisher    = {Curran Associates},
  title        = {{Cross-client label propagation for transductive and semi-supervised federated learning}},
  year         = {2023},
}

@inproceedings{14921,
  abstract     = {Neural collapse (NC) refers to the surprising structure of the last layer of deep neural networks in the terminal phase of gradient descent training. Recently, an increasing amount of experimental evidence has pointed to the propagation of NC to earlier layers of neural networks. However, while the NC in the last layer is well studied theoretically, much less is known about its multi-layered counterpart - deep neural collapse (DNC). In particular, existing work focuses either on linear layers or only on the last two layers at the price of an extra assumption. Our paper fills this gap by generalizing the established analytical framework for NC - the unconstrained features model - to multiple non-linear layers. Our key technical contribution is to show that, in a deep unconstrained features model, the unique global optimum for binary classification exhibits all the properties typical of DNC. This explains the existing experimental evidence of DNC. We also empirically show that (i) by optimizing deep unconstrained features models via gradient descent, the resulting solution agrees well with our theory, and (ii) trained networks recover the unconstrained features suitable for the occurrence of DNC, thus supporting the validity of this modeling principle.},
  author       = {Súkeník, Peter and Mondelli, Marco and Lampert, Christoph},
  booktitle    = {37th Annual Conference on Neural Information Processing Systems},
  location     = {New Orleans, LA, United States},
  title        = {{Deep neural collapse is provably optimal for the deep unconstrained features model}},
  year         = {2023},
}

@unpublished{15039,
  abstract     = {A crucial property for achieving secure, trustworthy and interpretable deep learning systems is their robustness: small changes to a system's inputs should not result in large changes to its outputs. Mathematically, this means one strives for networks with a small Lipschitz constant. Several recent works have focused on how to construct such Lipschitz networks, typically by imposing constraints on the weight matrices. In this work, we study an orthogonal aspect, namely the role of the activation function. We show that commonly used activation functions, such as MaxMin, as well as all piece-wise linear ones with two segments unnecessarily restrict the class of representable functions, even in the simplest one-dimensional setting. We furthermore introduce the new N-activation function that is provably more expressive than currently popular activation functions. We provide code at this https URL.},
  author       = {Prach, Bernd and Lampert, Christoph},
  booktitle    = {arXiv},
  title        = {{1-Lipschitz neural networks are more expressive with N-activations}},
  doi          = {10.48550/ARXIV.2311.06103},
  year         = {2023},
}

@phdthesis{13074,
  abstract     = {Deep learning has become an integral part of a large number of important applications, and many of the recent breakthroughs have been enabled by the ability to train very large models, capable to capture complex patterns and relationships from the data. At the same time, the massive sizes of modern deep learning models have made their deployment to smaller devices more challenging; this is particularly important, as in many applications the users rely on accurate deep learning predictions, but they only have access to devices with limited memory and compute power. One solution to this problem is to prune neural networks, by setting as many of their parameters as possible to zero, to obtain accurate sparse models with lower memory footprint. Despite the great research progress in obtaining sparse models that preserve accuracy, while satisfying memory and computational constraints, there are still many challenges associated with efficiently training sparse models, as well as understanding their generalization properties.

The focus of this thesis is to investigate how the training process of sparse models can be made more efficient, and to understand the differences between sparse and dense models in terms of how well they can generalize to changes in the data distribution. We first study a method for co-training sparse and dense models, at a lower cost compared to regular training. With our method we can obtain very accurate sparse networks, and dense models that can recover the baseline accuracy. Furthermore, we are able to more easily analyze the differences, at prediction level, between the sparse-dense model pairs. Next, we investigate the generalization properties of sparse neural networks in more detail, by studying how well different sparse models trained on a larger task can adapt to smaller, more specialized tasks, in a transfer learning scenario. Our analysis across multiple pruning methods and sparsity levels reveals that sparse models provide features that can transfer similarly to or better than the dense baseline. However, the choice of the pruning method plays an important role, and can influence the results when the features are fixed (linear finetuning), or when they are allowed to adapt to the new task (full finetuning). Using sparse models with fixed masks for finetuning on new tasks has an important practical advantage, as it enables training neural networks on smaller devices. However, one drawback of current pruning methods is that the entire training cycle has to be repeated to obtain the initial sparse model, for every sparsity target; in consequence, the entire training process is costly and also multiple models need to be stored. In the last part of the thesis we propose a method that can train accurate dense models that are compressible in a single step, to multiple sparsity levels, without additional finetuning. Our method results in sparse models that can be competitive with existing pruning methods, and which can also successfully generalize to new tasks.},
  author       = {Peste, Elena-Alexandra},
  issn         = {2663-337X},
  pages        = {147},
  publisher    = {Institute of Science and Technology Austria},
  title        = {{Efficiency and generalization of sparse neural networks}},
  doi          = {10.15479/at:ista:13074},
  year         = {2023},
}

@inproceedings{13053,
  abstract     = {Deep neural networks (DNNs) often have to be compressed, via pruning and/or quantization, before they can be deployed in practical settings. In this work we propose a new compression-aware minimizer dubbed CrAM that modifies the optimization step in a principled way, in order to produce models whose local loss behavior is stable under compression operations such as pruning. Thus, dense models trained via CrAM should be compressible post-training, in a single step, without significant accuracy loss. Experimental results on standard benchmarks, such as residual networks for ImageNet classification and BERT models for language modelling, show that CrAM produces dense models that can be more accurate than the standard SGD/Adam-based baselines, but which are stable under weight pruning: specifically, we can prune models in one-shot to 70-80% sparsity with almost no accuracy loss, and to 90% with reasonable (∼1%) accuracy loss, which is competitive with gradual compression methods. Additionally, CrAM can produce sparse models which perform well for transfer learning, and it also works for semi-structured 2:4 pruning patterns supported by GPU hardware. The code for reproducing the results is available at this https URL .},
  author       = {Peste, Elena-Alexandra and Vladu, Adrian and Kurtic, Eldar and Lampert, Christoph and Alistarh, Dan-Adrian},
  booktitle    = {11th International Conference on Learning Representations },
  location     = {Kigali, Rwanda },
  publisher    = {OpenReview},
  title        = {{CrAM: A Compression-Aware Minimizer}},
  year         = {2023},
}

@inproceedings{14771,
  abstract     = {Pruning—that is, setting a significant subset of the parameters of a neural network to zero—is one of the most popular methods of model compression. Yet, several recent works have raised the issue that pruning may induce or exacerbate bias in the output of the compressed model. Despite existing evidence for this phenomenon, the relationship between neural network pruning and induced bias is not well-understood. In this work, we systematically investigate and characterize this phenomenon in Convolutional Neural Networks for computer vision. First, we show that it is in fact possible to obtain highly-sparse models, e.g. with less than 10% remaining weights, which do not decrease in accuracy nor substantially increase in bias when compared to dense models. At the same time, we also find that, at higher sparsities, pruned models exhibit higher uncertainty in their outputs, as well as increased correlations, which we directly link to increased bias. We propose easy-to-use criteria which, based only on the uncompressed model, establish whether bias will increase with pruning, and identify the samples most susceptible to biased predictions post-compression. Our code can be found at https://github.com/IST-DASLab/pruned-vision-model-bias.},
  author       = {Iofinova, Eugenia B and Peste, Elena-Alexandra and Alistarh, Dan-Adrian},
  booktitle    = {2023 IEEE/CVF Conference on Computer Vision and Pattern Recognition},
  issn         = {2575-7075},
  location     = {Vancouver, BC, Canada},
  pages        = {24364--24373},
  publisher    = {IEEE},
  title        = {{Bias in pruned vision models: In-depth analysis and countermeasures}},
  doi          = {10.1109/cvpr52729.2023.02334},
  year         = {2023},
}

