We introduce a new tool for stochastic convex optimization (SCO): a Reweighted Stochastic Query (ReSQue) estimator for the gradient of a function convolved with a (Gaussian) probability density. Combining ReSQue with recent advances in ball oracle acceleration [CJJJLST20, ACJJS21], we develop algorithms achieving state-of-the-art complexities for SCO in parallel and private settings. For a SCO objective constrained to the unit ball in $\mathbb{R}^d$, we obtain the following results (up to polylogarithmic factors). We give a parallel algorithm obtaining optimization error $\epsilon_{\text{opt}}$ with $d^{1/3}\epsilon_{\text{opt}}^{-2/3}$ gradient oracle query depth and $d^{1/3}\epsilon_{\text{opt}}^{-2/3} + \epsilon_{\text{opt}}^{-2}$ gradient queries in total, assuming access to a bounded-variance stochastic gradient estimator. For $\epsilon_{\text{opt}} \in [d^{-1}, d^{-1/4}]$, our algorithm matches the state-of-the-art oracle depth of [BJLLS19] while maintaining the optimal total work of stochastic gradient descent. We give an $(\epsilon_{\text{dp}}, \delta)$-differentially private algorithm which, given $n$ samples of Lipschitz loss functions, obtains near-optimal optimization error and makes $\min(n, n^2\epsilon_{\text{dp}}^2 d^{-1}) + \min(n^{4/3}\epsilon_{\text{dp}}^{1/3}, (nd)^{2/3}\epsilon_{\text{dp}}^{-1})$ queries to the gradients of these functions. In the regime $d \le n \epsilon_{\text{dp}}^{2}$, where privacy comes at no cost in terms of the optimal loss up to constants, our algorithm uses $n + (nd)^{2/3}\epsilon_{\text{dp}}^{-1}$ queries and improves recent advancements of [KLL21, AFKT21]. In the moderately low-dimensional setting $d \le \sqrt n \epsilon_{\text{dp}}^{3/2}$, our query complexity is near-linear.
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我们提出了一个新的框架,用于对凸函数的差异私有优化,这些功能是任意规范$ \ normx {\ cdot} $中的Lipschitz。我们的算法基于一种正规的指数机制,该机制从密度$ \ propto \ exp(-k(f+\ mu r))$中进行样品,其中$ f $是经验损失,$ r $是一种常规化器,它与强烈的convex convex converize尊重$ \ normx {\ cdot} $,将\ cite {gll22}的最新作品推广到非Euclidean设置。我们表明,这种机制可以满足高斯差异隐私,并通过使用凸几何形状的本地化工具来解决DP-MER(经验风险最小化)和DP-SCO(随机凸优化)。我们的框架是第一个在一般规范空间中适用于私有凸优化的框架,并直接恢复了镜下下降的非私有SCO率,作为隐私参数$ \ eps \ to \ infty $。作为应用程序,对于LipsChitz优化了$ \ ell_p $ norms for(1,2)$中的所有$ p \ norms,我们获得了第一个最佳隐私性权衡权衡;对于$ p = 1 $,我们提高了最近的作品\ cite {asifkt21,bassilygn21}获得的权衡,至少通过对数因素。我们的$ \ ell_p $ norm和schatten- $ p $规范优化框架与多项式时间采样器相辅相成,我们的查询复杂性明确绑定。
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大型预审慎的模型可以私下微调以实现非私有模型的性能。这些结果中的一个共同主题是令人惊讶的观察结果,即高维模型可以实现有利的隐私性权衡。这似乎与差异私有凸学习的模型尺寸依赖性相矛盾,并提出了以下研究问题:差异私人学习的性能何时不会随着模型大小的增加而降低?我们确定投影到子空间上的梯度的幅度是决定性能的关键因素。为了确切地为私人凸学习的特征,我们引入了一个条件,即我们将限制Lipschitz的连续性限制并得出了在其他条件下与维度无关的过多经验和人口风险的界限。我们从经验上表明,在大型语言模型的私人微调中,在本地最佳距离附近评估的梯度主要由一些主要组件控制。这种行为类似于我们在凸面设置中获得尺寸独立界限的条件。我们的理论和经验结果共同为大规模私人微调成功提供了可能的解释。
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在本文中,我们研究了非平滑凸函数的私人优化问题$ f(x)= \ mathbb {e} _i f_i(x)$ on $ \ mathbb {r}^d $。我们表明,通过将$ \ ell_2^2 $正规器添加到$ f(x)$并从$ \ pi(x)\ propto \ exp(-k(f(x)+\ mu \ \ | | x \ | _2^2/2))$恢复已知的最佳经验风险和$(\ epsilon,\ delta)$ - dp的已知最佳经验风险和人口损失。此外,我们将展示如何使用$ \ widetilde {o}(n \ min(d,n))$ QUERIES $ QUERIES $ f_i(x)$用于DP-SCO,其中$ n $是示例数/用户和$ d $是环境维度。我们还在评估查询的数量上给出了一个(几乎)匹配的下限$ \ widetilde {\ omega}(n \ min(d,n))$。我们的结果利用以下具有独立感兴趣的工具:(1)如果损失函数强烈凸出并且扰动是Lipschitz,则证明指数机制的高斯差异隐私(GDP)。我们的隐私约束是\ emph {optimal},因为它包括高斯机制的隐私性,并使用等仪不等式证明了强烈的对数concove措施。 (2)我们展示如何从$ \ exp(-f(x) - \ mu \ | x \ | |^2_2/2)$ g $ -lipschitz $ f $带有$ \ eta $的总变化中的错误(电视)使用$ \ widetilde {o}((g^2/\ mu)\ log^2(d/\ eta))$无偏查询到$ f(x)$。这是第一个在dimension $ d $和精度$ \ eta $上具有\ emph {polylogarithmic依赖的查询复杂性的采样器。
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In this paper, we propose a robust 3D detector, named Cross Modal Transformer (CMT), for end-to-end 3D multi-modal detection. Without explicit view transformation, CMT takes the image and point clouds tokens as inputs and directly outputs accurate 3D bounding boxes. The spatial alignment of multi-modal tokens is performed implicitly, by encoding the 3D points into multi-modal features. The core design of CMT is quite simple while its performance is impressive. CMT obtains 73.0% NDS on nuScenes benchmark. Moreover, CMT has a strong robustness even if the LiDAR is missing. Code will be released at https://github.com/junjie18/CMT.
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Dataset distillation has emerged as a prominent technique to improve data efficiency when training machine learning models. It encapsulates the knowledge from a large dataset into a smaller synthetic dataset. A model trained on this smaller distilled dataset can attain comparable performance to a model trained on the original training dataset. However, the existing dataset distillation techniques mainly aim at achieving the best trade-off between resource usage efficiency and model utility. The security risks stemming from them have not been explored. This study performs the first backdoor attack against the models trained on the data distilled by dataset distillation models in the image domain. Concretely, we inject triggers into the synthetic data during the distillation procedure rather than during the model training stage, where all previous attacks are performed. We propose two types of backdoor attacks, namely NAIVEATTACK and DOORPING. NAIVEATTACK simply adds triggers to the raw data at the initial distillation phase, while DOORPING iteratively updates the triggers during the entire distillation procedure. We conduct extensive evaluations on multiple datasets, architectures, and dataset distillation techniques. Empirical evaluation shows that NAIVEATTACK achieves decent attack success rate (ASR) scores in some cases, while DOORPING reaches higher ASR scores (close to 1.0) in all cases. Furthermore, we conduct a comprehensive ablation study to analyze the factors that may affect the attack performance. Finally, we evaluate multiple defense mechanisms against our backdoor attacks and show that our attacks can practically circumvent these defense mechanisms.
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Few Shot Instance Segmentation (FSIS) requires models to detect and segment novel classes with limited several support examples. In this work, we explore a simple yet unified solution for FSIS as well as its incremental variants, and introduce a new framework named Reference Twice (RefT) to fully explore the relationship between support/query features based on a Transformer-like framework. Our key insights are two folds: Firstly, with the aid of support masks, we can generate dynamic class centers more appropriately to re-weight query features. Secondly, we find that support object queries have already encoded key factors after base training. In this way, the query features can be enhanced twice from two aspects, i.e., feature-level and instance-level. In particular, we firstly design a mask-based dynamic weighting module to enhance support features and then propose to link object queries for better calibration via cross-attention. After the above steps, the novel classes can be improved significantly over our strong baseline. Additionally, our new framework can be easily extended to incremental FSIS with minor modification. When benchmarking results on the COCO dataset for FSIS, gFSIS, and iFSIS settings, our method achieves a competitive performance compared to existing approaches across different shots, e.g., we boost nAP by noticeable +8.2/+9.4 over the current state-of-the-art FSIS method for 10/30-shot. We further demonstrate the superiority of our approach on Few Shot Object Detection. Code and model will be available.
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This paper focuses on designing efficient models with low parameters and FLOPs for dense predictions. Even though CNN-based lightweight methods have achieved stunning results after years of research, trading-off model accuracy and constrained resources still need further improvements. This work rethinks the essential unity of efficient Inverted Residual Block in MobileNetv2 and effective Transformer in ViT, inductively abstracting a general concept of Meta-Mobile Block, and we argue that the specific instantiation is very important to model performance though sharing the same framework. Motivated by this phenomenon, we deduce a simple yet efficient modern \textbf{I}nverted \textbf{R}esidual \textbf{M}obile \textbf{B}lock (iRMB) for mobile applications, which absorbs CNN-like efficiency to model short-distance dependency and Transformer-like dynamic modeling capability to learn long-distance interactions. Furthermore, we design a ResNet-like 4-phase \textbf{E}fficient \textbf{MO}del (EMO) based only on a series of iRMBs for dense applications. Massive experiments on ImageNet-1K, COCO2017, and ADE20K benchmarks demonstrate the superiority of our EMO over state-of-the-art methods, \eg, our EMO-1M/2M/5M achieve 71.5, 75.1, and 78.4 Top-1 that surpass \textbf{SoTA} CNN-/Transformer-based models, while trading-off the model accuracy and efficiency well.
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Benefiting from the intrinsic supervision information exploitation capability, contrastive learning has achieved promising performance in the field of deep graph clustering recently. However, we observe that two drawbacks of the positive and negative sample construction mechanisms limit the performance of existing algorithms from further improvement. 1) The quality of positive samples heavily depends on the carefully designed data augmentations, while inappropriate data augmentations would easily lead to the semantic drift and indiscriminative positive samples. 2) The constructed negative samples are not reliable for ignoring important clustering information. To solve these problems, we propose a Cluster-guided Contrastive deep Graph Clustering network (CCGC) by mining the intrinsic supervision information in the high-confidence clustering results. Specifically, instead of conducting complex node or edge perturbation, we construct two views of the graph by designing special Siamese encoders whose weights are not shared between the sibling sub-networks. Then, guided by the high-confidence clustering information, we carefully select and construct the positive samples from the same high-confidence cluster in two views. Moreover, to construct semantic meaningful negative sample pairs, we regard the centers of different high-confidence clusters as negative samples, thus improving the discriminative capability and reliability of the constructed sample pairs. Lastly, we design an objective function to pull close the samples from the same cluster while pushing away those from other clusters by maximizing and minimizing the cross-view cosine similarity between positive and negative samples. Extensive experimental results on six datasets demonstrate the effectiveness of CCGC compared with the existing state-of-the-art algorithms.
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As one of the prevalent methods to achieve automation systems, Imitation Learning (IL) presents a promising performance in a wide range of domains. However, despite the considerable improvement in policy performance, the corresponding research on the explainability of IL models is still limited. Inspired by the recent approaches in explainable artificial intelligence methods, we proposed a model-agnostic explaining framework for IL models called R2RISE. R2RISE aims to explain the overall policy performance with respect to the frames in demonstrations. It iteratively retrains the black-box IL model from the randomized masked demonstrations and uses the conventional evaluation outcome environment returns as the coefficient to build an importance map. We also conducted experiments to investigate three major questions concerning frames' importance equality, the effectiveness of the importance map, and connections between importance maps from different IL models. The result shows that R2RISE successfully distinguishes important frames from the demonstrations.
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