324 research outputs found

    Stimulus Temporal Coherence Strongly Influences Rapid Plasticity in Primary Auditory Cortex under Global Attention

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    Temporal coherence of stimulus features is a key property of sounds that emanate from single source. Consequently, it is important to understand how it may influence the direction and extent of the rapid plasticity postulated to occur during the streaming of concurrent sounds. We postulated that when animals listen attentively to coherent or incoherent stimuli, responses would adapt to effectively encode the correlational structure of the stimuli. In this study, ferrets were trained to attend globally to two-tone sequences which were played either simultaneously (SYNC) or alternatively (ALT) on a trial-by-trial basis, and to detect a transition to a random cloud of tones by licking a waterspout for reward. Neuronal activities were collected in the primary auditory cortex during performing the task and passively listening to the same stimuli sequences. Compared with the passive condition, neuronal responses changed distinctively between SYNC and ALT trials under the effect of attention. These results provide neuronal evidence for the role of stimulus temporal coherence in modulating responses during attentive listening to complex sounds

    Sampling-based Fast Gradient Rescaling Method for Highly Transferable Adversarial Attacks

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    Deep neural networks are known to be vulnerable to adversarial examples crafted by adding human-imperceptible perturbations to the benign input. After achieving nearly 100% attack success rates in white-box setting, more focus is shifted to black-box attacks, of which the transferability of adversarial examples has gained significant attention. In either case, the common gradient-based methods generally use the sign function to generate perturbations on the gradient update, that offers a roughly correct direction and has gained great success. But little work pays attention to its possible limitation. In this work, we observe that the deviation between the original gradient and the generated noise may lead to inaccurate gradient update estimation and suboptimal solutions for adversarial transferability. To this end, we propose a Sampling-based Fast Gradient Rescaling Method (S-FGRM). Specifically, we use data rescaling to substitute the sign function without extra computational cost. We further propose a Depth First Sampling method to eliminate the fluctuation of rescaling and stabilize the gradient update. Our method could be used in any gradient-based attacks and is extensible to be integrated with various input transformation or ensemble methods to further improve the adversarial transferability. Extensive experiments on the standard ImageNet dataset show that our method could significantly boost the transferability of gradient-based attacks and outperform the state-of-the-art baselines.Comment: 10 pages, 6 figures, 7 tables. arXiv admin note: substantial text overlap with arXiv:2204.0288

    The Role of AM Symbiosis in Plant Adaptation to Drought Stress

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    Symposium paper Part 1: Function and management of soil microorganisms in agro-ecosystems with special reference to arbuscular mycorrhizal fung

    FDNeRF: Semantics-Driven Face Reconstruction, Prompt Editing and Relighting with Diffusion Models

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    The ability to create high-quality 3D faces from a single image has become increasingly important with wide applications in video conferencing, AR/VR, and advanced video editing in movie industries. In this paper, we propose Face Diffusion NeRF (FDNeRF), a new generative method to reconstruct high-quality Face NeRFs from single images, complete with semantic editing and relighting capabilities. FDNeRF utilizes high-resolution 3D GAN inversion and expertly trained 2D latent-diffusion model, allowing users to manipulate and construct Face NeRFs in zero-shot learning without the need for explicit 3D data. With carefully designed illumination and identity preserving loss, as well as multi-modal pre-training, FD-NeRF offers users unparalleled control over the editing process enabling them to create and edit face NeRFs using just single-view images, text prompts, and explicit target lighting. The advanced features of FDNeRF have been designed to produce more impressive results than existing 2D editing approaches that rely on 2D segmentation maps for editable attributes. Experiments show that our FDNeRF achieves exceptionally realistic results and unprecedented flexibility in editing compared with state-of-the-art 3D face reconstruction and editing methods. Our code will be available at https://github.com/BillyXYB/FDNeRF

    Effective and Robust Detection of Adversarial Examples via Benford-Fourier Coefficients

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    Adversarial examples have been well known as a serious threat to deep neural networks (DNNs). In this work, we study the detection of adversarial examples, based on the assumption that the output and internal responses of one DNN model for both adversarial and benign examples follow the generalized Gaussian distribution (GGD), but with different parameters (i.e., shape factor, mean, and variance). GGD is a general distribution family to cover many popular distributions (e.g., Laplacian, Gaussian, or uniform). It is more likely to approximate the intrinsic distributions of internal responses than any specific distribution. Besides, since the shape factor is more robust to different databases rather than the other two parameters, we propose to construct discriminative features via the shape factor for adversarial detection, employing the magnitude of Benford-Fourier coefficients (MBF), which can be easily estimated using responses. Finally, a support vector machine is trained as the adversarial detector through leveraging the MBF features. Extensive experiments in terms of image classification demonstrate that the proposed detector is much more effective and robust on detecting adversarial examples of different crafting methods and different sources, compared to state-of-the-art adversarial detection methods
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