nils-herrmann/clean_scirepeval huggingface dataset:
Structural Language Models for Any-Code Generation
Authors: Uri Alon, Roy Sadaka, Omer Levy, Eran Yahav

We address the problem of Any-Code Generation (AnyGen) - generating code without any restriction on the vocabulary or structure. The state-of-the-art in this problem is the sequence-to-sequence (seq2seq) approach, which treats code as a sequence and does not leverage any structural information. We introduce a new approach to AnyGen that leverages the strict syntax of programming languages to model a code snippet as tree structural language modeling (SLM). SLM estimates the probability of the program's abstract syntax tree (AST) by decomposing it into a product of conditional probabilities over its nodes. We present a neural model that computes these conditional probabilities by considering all AST paths leading to a target node. Unlike previous structural techniques that have severely restricted the kinds of expressions that can be generated, our approach can generate arbitrary expressions in any programming language. Our model significantly outperforms both seq2seq and a variety of existing structured approaches in generating Java and C# code. We make our code, datasets, and models available online.
Walking on the Edge: Fast, Low-Distortion Adversarial Examples
Authors: Hanwei Zhang, Teddy Furon, Yannis Avrithis, Laurent Amsaleg

Adversarial examples of deep neural networks are receiving ever increasing attention because they help in understanding and reducing the sensitivity to their input. This is natural given the increasing applications of deep neural networks in our everyday lives. When white-box attacks are almost always successful, it is typically only the distortion of the perturbations that matters in their evaluation.

In this work, we argue that speed is important as well, especially when considering that fast attacks are required by adversarial training. Given more time, iterative methods can always find better solutions. We investigate this speed-distortion trade-off in some depth and introduce a new attack called boundary projection BP that improves upon existing methods by a large margin. Our key idea is that the classification boundary is a manifold in the image space: we therefore quickly reach the boundary and then optimize distortion on this manifold.
Adversarial Robustness as a Prior for Learned Representations
Authors: Logan Engstrom, Andrew Ilyas, Shibani Santurkar, Dimitris Tsipras, Brandon Tran, Aleksander Madry

An important goal in deep learning is to learn versatile, high-level feature representations of input data. However, standard networks' representations seem to possess shortcomings that, as we illustrate, prevent them from fully realizing this goal. In this work, we show that robust optimization can be re-cast as a tool for enforcing priors on the features learned by deep neural networks. It turns out that representations learned by robust models address the aforementioned shortcomings and make significant progress towards learning a high-level encoding of inputs. In particular, these representations are approximately invertible, while allowing for direct visualization and manipulation of salient input features. More broadly, our results indicate adversarial robustness as a promising avenue for improving learned representations.
Self-supervised Training of Proposal-based Segmentation via Background Prediction
Authors: Isinsu Katircioglu, Helge Rhodin, Victor Constantin, Jörg Spörri, Mathieu Salzmann, Pascal Fua

While supervised object detection and segmentation methods achieve impressive accuracy, they generalize poorly to images whose appearance significantly differs from the data they have been trained on. To address this in scenarios where annotating data is prohibitively expensive, we introduce a self-supervised approach to detection and segmentation, able to work with monocular images captured with a moving camera. At the heart of our approach lies the observations that object segmentation and background reconstruction are linked tasks, and that, for structured scenes, background regions can be re-synthesized from their surroundings, whereas regions depicting the object cannot.
We encode this intuition as a self-supervised loss function that we exploit to train a proposal-based segmentation network. To account for the discrete nature of the proposals, we develop a Monte Carlo-based training strategy that allows the algorithm to explore the large space of object proposals. We apply our method to human detection and segmentation in images that visually depart from those of standard benchmarks, achieving competitive results compared to the few existing self-supervised methods and approaching the accuracy of supervised ones that exploit large annotated datasets.
Decision boundary variability and generalization in neural networks
Authors: Shiye Lei, Fengxiang He, Yancheng Yuan, Dacheng Tao

Existing works suggest that the generalizability is guaranteed when the margin between data and decision boundaries is sufficiently large. However, the existence of adversarial examples in neural networks shows that excellent generalization and small margin can exist simultaneously, which casts shadows to the current understanding. This paper discovers that the neural network with lower decision boundary (DB) variability has better generalizability. Two new notions, algorithm DB variability and $(\epsilon, \eta)$-data DB variability, are proposed to measure the decision boundary variability from the algorithm and data perspectives. Extensive experiments show significant negative correlations between the decision boundary variability and the generalizability. From the theoretical view, we prove two lower bounds and two upper bounds of the generalization error based on the decision boundary variability, which is consistent with our empirical results. Moreover, the bounds do not explicitly depend on the network size, which is usually prohibitively large in deep learning.
Defending Against Backdoor Attacks Using Ensembles of Weak Learners 
Authors: Charles Jin, Melinda Sun, Martin Rinard

A recent line of work has shown that deep networks are susceptible to backdoor data poisoning attacks. Specifically, by injecting a small amount of malicious data into the training distribution, an adversary gains the ability to control the behavior of the model during inference. We propose an iterative training procedure for removing poisoned data from the training set. Our approach consists of two steps. We first train an ensemble of weak learners to automatically discover distinct subpopulations in the training set. We then leverage a boosting framework to exclude the poisoned data and recover the clean data. Our algorithm is based on a novel bootstrapped measure of generalization, which provably separates the clean from the dirty data under mild assumptions. Empirically, our method successfully defends against a state-of-the-art dirty label backdoor attack. We find that our approach significantly outperforms previous defenses.
LSH-SAMPLING BREAKS THE COMPUTATIONAL CHICKEN-AND-EGG LOOP IN ADAPTIVE STOCHASTIC GRADIENT ESTIMATION
Authors: Beidi Chen, Yingchen Xu, Anshumali Shrivastava

Stochastic Gradient Descent or SGD is the most popular optimization algorithm for large-scale problems. SGD estimates the gradient by uniform sampling with sample size one. There have been several other works that suggest faster epoch wise convergence by using weighted non-uniform sampling for better gradient estimates. Unfortunately, the per-iteration cost of maintaining this adaptive distribution for gradient estimation is more than calculating the full gradient. As a result, the false impression of faster convergence in iterations leads to slower convergence in time, which we call a chicken-and-egg loop. In this paper, we break this barrier by providing the first demonstration of a sampling scheme, which leads to superior gradient estimation, while keeping the sampling cost per iteration similar to that of the uniform sampling. Such an algorithm is possible due to the sampling view of Locality Sensitive Hashing (LSH), which came to light recently. As a consequence of superior and fast estimation, we reduce the running time of all existing gradient descent algorithms. We demonstrate the benefits of our proposal on both SGD and AdaGrad.
Robust Learning via Golden Symmetric Loss of (un)Trusted Labels
Authors: Amirmasoud Ghiassi, Robert Birke, Lydia Y. Chen

Learning robust deep models against noisy labels becomes ever critical when today's data is commonly collected from open platforms and subject to adversarial corruption. The information on the label corruption process, i.e., corruption matrix, can greatly enhance the robustness of deep models but still fall behind in combating hard classes. In this paper, we propose to construct a golden symmetric loss (GSL) based on the estimated confusion matrix as to avoid overfitting to noisy labels and learn effectively from hard classes. GSL is the weighted sum of the corrected regular cross entropy and reverse cross entropy. By leveraging a small fraction of trusted clean data, we estimate the corruption matrix and use it to correct the loss as well as to determine the weights of GSL. We theoretically prove the robustness of the proposed loss function in the presence of dirty labels. We provide a heuristics to adaptively tune the loss weights of GSL according to the noise rate and diversity measured from the dataset. We evaluate our proposed golden symmetric loss on both vision and natural language deep models subject to different types of label noise patterns. Empirical results show that GSL can significantly outperform the existing robust training methods on different noise patterns, showing accuracy improvement up to 18% on CIFAR-100 and 1% on real world noisy dataset of Clothing1M.
Structured consistency loss for semi-supervised semantic segmentation
Authors: JongMok Kim, Joo Young Jang, Hyunwoo Park

The consistency loss has played a key role in solving problems in recent studies on semi-supervised learning. Yet extant studies with the consistency loss are limited to its application to classification tasks; extant studies on semi-supervised semantic segmentation rely on pixel-wise classification, which does not reflect the structured nature of characteristics in prediction. We propose a structured consistency loss to address this limitation of extant studies. Structured consistency loss promotes consistency in inter-pixel similarity between teacher and student networks. Specifically, collaboration with CutMix optimizes the efficient performance of semi-supervised semantic segmentation with structured consistency loss by reducing computational burden dramatically. The superiority of proposed method is verified with the Cityscapes; The Cityscapes benchmark results with validation and with test data are 81.9 mIoU and 83.84 mIoU respectively. This ranks the first place on the pixel-level semantic labeling task of Cityscapes benchmark suite. To the best of our knowledge, we are the first to present the superiority of state-of-the-art semi-supervised learning in semantic segmentation.
Discovering Low-Precision Networks Close to Full-Precision Networks for Efficient Embedded Inference
Authors: Jeffrey L. McKinstry, Steven K. Esser, Rathinakumar Appuswamy, Deepika Bablani, John V. Arthur, Izzet B. Yildiz, Dharmendra S. Modha

To realize the promise of ubiquitous embedded deep network inference, it is essential to seek limits of energy and area efficiency.  To this end, low-precision networks offer tremendous promise because both energy and area scale down quadratically with the reduction in precision.  Here, for the first time, we demonstrate ResNet-18, ResNet-34, ResNet-50, ResNet-152, Inception-v3, densenet-161, and VGG-16bn networks on the ImageNet classification benchmark that, at 8-bit precision exceed the accuracy of the full-precision baseline networks after one epoch of finetuning, thereby leveraging the availability of pretrained models.
We also demonstrate ResNet-18, ResNet-34, and ResNet-50 4-bit models that match the accuracy of the full-precision baseline networks -- the highest scores to date. Surprisingly, the weights of the low-precision networks are very close (in cosine similarity) to the weights of the corresponding baseline networks, making training from scratch unnecessary.

We find that gradient noise due to quantization during training increases with reduced precision, and seek ways to overcome this noise. The number of iterations required by stochastic gradient descent to achieve a given training error is related to the square of (a) the distance of the initial solution from the final plus (b) the maximum variance of the gradient estimates.  By drawing inspiration from this observation, we (a) reduce solution distance by starting with pretrained fp32 precision baseline networks and fine-tuning, and (b) combat noise introduced by quantizing weights and activations during training, by using larger batches along with matched learning rate annealing.  Sensitivity analysis indicates that these techniques, coupled with proper activation function range calibration, offer a promising heuristic to discover low-precision networks, if they exist, close to fp32 precision baseline networks.
Preventing Value Function Collapse in Ensemble  Q-Learning by Maximizing Representation Diversity
Authors: Hassam Sheikh, Ladislau Boloni

The first deep RL algorithm, DQN, was limited by the overestimation bias of the learned Q-function. Subsequent algorithms proposed techniques to reduce this problem, without fully eliminating it. Recently, the Maxmin and Ensemble Q-learning algorithms used the different estimates provided by ensembles of learners to reduce the bias. Unfortunately, these learners can converge to the same point in the parametric or representation space, falling back to the classic single neural network DQN. In this paper, we describe a regularization technique to maximize diversity in the representation space in these algorithms. We propose and compare five regularization functions inspired from economics theory and consensus optimization. We show that the resulting approach significantly outperforms the Maxmin and Ensemble Q-learning algorithms as well as non-ensemble baselines.
Boundary Effects in CNNs: Feature or Bug?
Authors: Md Amirul Islam, Matthew Kowal, Sen Jia, Konstantinos G. Derpanis, Neil Bruce

Recent studies have shown that the addition of zero padding drives convolutional neural networks (CNNs) to encode a significant amount of absolute position information in their internal representations, while a lack of padding precludes position encoding. Additionally, various studies have used image patches on background canvases (e.g., to accommodate that inputs to CNNs must be rectangular) without consideration that different backgrounds may contain varying levels of position information according to their color. These studies give rise to deeper questions about the role of boundary information in CNNs, that are explored in this paper: (i) What boundary heuristics (e.g., padding type, canvas color) enable optimal encoding of absolute position information for a particular downstream task?; (ii) Where in the latent representations do boundary effects destroy semantic and location information?; (iii) Does encoding position information affect the learning of semantic representations?; (iv) Does encoding position information always improve performance? To provide answers to these questions, we perform the largest case study to date on the role that padding and border heuristics play in CNNs. We first show that zero padding injects optimal position information into CNNs relative to other common padding types. We then design a series of novel tasks which allow us to accurately quantify boundary effects as a function of the distance to the border. A number of semantic objectives reveal the destructive effect of dealing with the border on semantic representations. Further, we demonstrate that the encoding of position information improves separability of learned semantic features. Finally, we demonstrate the implications of these findings on a number of real-world tasks to show that position information can act as a feature or a bug.
Later Span Adaptation for Language Understanding
Authors: Rongzhou Bao, Zhuosheng Zhang, hai zhao

Pre-trained contextualized language models (PrLMs) broadly use fine-grained tokens (words or sub-words) as minimal linguistic unit in pre-training phase. Introducing span-level information in pre-training has shown capable of further enhancing PrLMs. However, such methods require enormous resources and are lack of adaptivity due to huge computational requirement from pre-training. Instead of too early fixing the linguistic unit  input as nearly all previous work did, we propose a novel method that combines span-level information into the representations generated by PrLMs during fine-tuning phase for better flexibility. In this way, the modeling procedure of span-level texts can be more adaptive to different downstream tasks. In detail, we divide the sentence into several spans according to the segmentation generated by a pre-sampled dictionary. Based on the sub-token-level representation provided by PrLMs, we enhance the connection between the tokens in each span and gain a representation with enhanced span-level information. Experiments are conducted on GLUE benchmark and prove that our approach could remarkably enhance the performance of PrLMs in various natural language understanding tasks.
BDS-GCN: Efficient Full-Graph Training of Graph Convolutional Nets with Partition-Parallelism and Boundary Sampling
Authors: Cheng Wan, Youjie Li, Nam Sung Kim, Yingyan Lin

Graph Convolutional Networks (GCNs) have emerged as the state-of-the-art model for graph-based learning tasks. However, it is still challenging to train GCNs at scale, limiting their applications to real-world large graphs and hindering the exploration of deeper and more sophisticated GCN architectures. While it can be natural to leverage graph partition and distributed training for tackling this challenge, this direction has only been slightly touched on previously due to the unique challenge posed by the GCN structures, especially the excessive amount of boundary nodes in each partitioned subgraph, which can easily explode the required memory and communications for distributed training of GCNs. To this end, we propose BDS-GCN, a method that adopts unbiased boundary sampling strategy to enable efficient and scalable distributed GCN training while maintaining the full-graph accuracy. Empirical evaluations and ablation studies validate the effectiveness of the proposed BDS-GCN, e.g., boosting the throughput by up-to 500% and reducing the memory usage by up-to 58% for distributed GCN training, while achieving the same accuracy, as compared with the state-of-the-art methods. We believe our BDS-GCN would open up a new paradigm for enabling GCN training at scale. All code will be released publicly upon acceptance.
Learning Dynamic State Abstractions for Model-Based Reinforcement Learning
Authors: Lars Buesing, Theophane Weber, Sebastien Racaniere, S. M. Ali Eslami, Danilo Rezende, David Reichert, Fabio Viola, Frederic Besse, Karol Gregor, Demis Hassabis, Daan Wierstra

A key challenge in model-based reinforcement learning (RL) is to synthesize computationally efficient and accurate environment models. We show that carefully designed models that learn predictive and compact state representations, also called state-space models, substantially reduce the computational costs for predicting outcomes of sequences of actions. Extensive experiments establish that state-space models accurately capture the dynamics of Atari games from the Arcade Learning Environment (ALE) from raw pixels. Furthermore, RL agents that use Monte-Carlo rollouts of these models as features for decision making outperform strong model-free baselines on the game MS_PACMAN, demonstrating the benefits of planning using learned dynamic state abstractions.
Sorting out Lipschitz function approximation
Authors: Cem Anil, James Lucas, Roger B. Grosse

Training neural networks subject to a Lipschitz constraint is useful for generalization bounds, provable adversarial robustness, interpretable gradients, and Wasserstein distance estimation. By the composition property of Lipschitz functions, it suffices to ensure that each individual affine transformation or nonlinear activation function is 1-Lipschitz. The challenge is to do this while maintaining the expressive power.  We identify a necessary property for such an architecture: each of the layers must preserve the gradient norm during backpropagation. Based on this, we propose to combine a gradient norm preserving activation function, GroupSort, with norm-constrained weight matrices. We show that norm-constrained GroupSort architectures are universal Lipschitz function approximators. Empirically, we show that norm-constrained GroupSort networks achieve tighter estimates of Wasserstein distance than their ReLU counterparts and can achieve provable adversarial robustness guarantees with little cost to accuracy.
Bayesian Residual Policy Optimization: Scalable Bayesian Reinforcement Learning with Clairvoyant Experts
Authors: Gilwoo Lee, Brian Hou, Sanjiban Choudhury, Siddhartha S. Srinivasa

Informed and robust decision making in the face of uncertainty is critical for robots that perform physical tasks alongside people. We formulate this as a Bayesian Reinforcement Learning problem over latent Markov Decision Processes (MDPs). While Bayes-optimality is theoretically the gold standard, existing algorithms do not scale well to continuous state and action spaces. We propose a scalable solution that builds on the following insight: in the absence of uncertainty, each latent MDP is easier to solve. We split the challenge into two simpler components. First, we obtain an ensemble of clairvoyant experts and fuse their advice to compute a baseline policy. Second, we train a Bayesian residual policy to improve upon the ensemble's recommendation and learn to reduce uncertainty. Our algorithm, Bayesian Residual Policy Optimization (BRPO), imports the scalability of policy gradient methods as well as the initialization from prior models. BRPO significantly improves the ensemble of experts and drastically outperforms existing adaptive RL methods.
Reduced-Gate Convolutional LSTM Design Using Predictive Coding for Next-Frame Video Prediction
Authors: Nelly Elsayed, Anthony S. Maida, Magdy Bayoumi

Spatiotemporal sequence prediction is an important problem in deep learning. We
study next-frame video prediction using a deep-learning-based predictive coding
framework that uses convolutional, long short-term memory (convLSTM) modules.
We introduce a novel reduced-gate convolutional LSTM architecture. Our
reduced-gate model achieves better next-frame prediction accuracy than the original
convolutional LSTM while using a smaller parameter budget, thereby reducing
training time. We tested our reduced gate modules within a predictive coding architecture
on the moving MNIST and KITTI datasets. We found that our reduced-gate
model has a significant reduction of approximately 40 percent of the total
number of training parameters and training time in comparison with the standard
LSTM model which makes it attractive for hardware implementation especially
on small devices.