Federated embodied agent learning protects the data privacy of individual visual environments by keeping data locally at each client (the individual environment) during training. However, since the local data is inaccessible to the server under federated learning, attackers may easily poison the training data of the local client to build a backdoor in the agent without notice. Deploying such an agent raises the risk of potential harm to humans, as the attackers may easily navigate and control the agent as they wish via the backdoor. Towards Byzantine-robust federated embodied agent learning, in this paper, we study the attack and defense for the task of vision-and-language navigation (VLN), where the agent is required to follow natural language instructions to navigate indoor environments. First, we introduce a simple but effective attack strategy, Navigation as Wish (NAW), in which the malicious client manipulates local trajectory data to implant a backdoor into the global model. Results on two VLN datasets (R2R and RxR) show that NAW can easily navigate the deployed VLN agent regardless of the language instruction, without affecting its performance on normal test sets. Then, we propose a new Prompt-Based Aggregation (PBA) to defend against the NAW attack in federated VLN, which provides the server with a ''prompt'' of the vision-and-language alignment variance between the benign and malicious clients so that they can be distinguished during training. We validate the effectiveness of the PBA method on protecting the global model from the NAW attack, which outperforms other state-of-the-art defense methods by a large margin in the defense metrics on R2R and RxR.
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建立一个对话体现的代理执行现实生活任务一直是一个长期而又具有挑战性的研究目标,因为它需要有效的人类代理沟通,多模式理解,远程顺序决策等。传统的符号方法具有扩展和概括问题,而端到端的深度学习模型则遭受数据稀缺和高任务复杂性的影响,并且通常很难解释。为了从两全其美的世界中受益,我们提出了一个神经符号常识性推理(JARVIS)框架,用于模块化,可推广和可解释的对话体现的药物。首先,它通过提示大型语言模型(LLM)来获得符号表示,以了解语言理解和次目标计划,并通过从视觉观察中构建语义图。然后,基于任务和动作级别的常识,次目标计划和行动生成的符号模块。在Teach数据集上进行的大量实验验证了我们的JARVIS框架的功效和效率,该框架在所有三个基于对话框的具体任务上实现了最新的(SOTA)结果,包括对话记录(EDH)的执行,对话框的轨迹, (TFD)和两个代理任务完成(TATC)(例如,我们的方法将EDH看不见的成功率从6.1 \%\%提高到15.8 \%)。此外,我们系统地分析了影响任务绩效的基本因素,并在几个射击设置中证明了我们方法的优越性。我们的Jarvis模型在Alexa奖Simbot公共基准挑战赛中排名第一。
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我们考虑对重尾数据的随机凸优化,并保证成为私人(DP)。此问题的先前工作仅限于梯度下降(GD)方法,这对于大规模问题效率低下。在本文中,我们解决了此问题,并通过剪辑得出了私人随机方法的第一个高概率范围。对于一般凸问题,我们得出过多的人口风险$ \ tilde {o} \ left(\ frac {d^{1/7} \ sqrt {\ ln \ frac {(n \ epsilon) }}} {(n \ epsilon)^{2/7}}} \ right)$和$ \ tilde {o} \ left(\ frac {d^{1/7} \ ln \ ln \ frac {(n \ epsilon)^(n \ epsilon)^ 2} {\ beta d}} {(n \ epsilon)^{2/7}}} \ right)$分别在有限或无限的域假设下(此处$ n $是样本大小,$ d $是数据,$ \ beta $是置信度,$ \ epsilon $是私人级别)。然后,我们将分析扩展到强烈的凸情况和非平滑案例(可用于使用H $ \ ddot {\ text {o}} $ lder-lder-continuule梯度的通用光滑目标)。我们建立了新的超额风险界限,而没有有限的域名。在相应情况下,上面的结果比现有方法降低了多余的风险和梯度复杂性。进行数值实验以证明理论改进是合理的。
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尽管不变风险最小化(IRM)成功解决了分布式概括问题,但在实践中应用时,IRM仍可以损害最佳性。 IRM的实用变体,例如IRMV1,已被证明与IRM存在显着差距,因此即使在简单的问题中也可能无法捕获不变性。此外,IRMV1中的优化过程涉及两个内在冲突的目标,并且通常需要对客观权重进行仔细的调整。为了纠正上述问题,我们将IRM重新制定为多目标优化问题,并为IRM提出了一种新的优化方案,称为Pareto不变风险最小化(Pair)。对可以在客观冲突下适应优化指导。此外,我们表明对可以赋予实用的IRM变体能够在提供适当的指导时用原始IRM克服障碍。我们对ColoredMnist进行实验,以确认我们的理论和对的有效性。
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当有大量的计算资源可用时,AutoAttack(AA)是评估对抗性鲁棒性的最可靠方法。但是,高计算成本(例如,比项目梯度下降攻击的100倍)使AA对于具有有限计算资源的从业者来说是不可行的,并且也阻碍了AA在对抗培训中的应用(AT)。在本文中,我们提出了一种新颖的方法,即最小利润率(MM)攻击,以快速可靠地评估对抗性鲁棒性。与AA相比,我们的方法可实现可比的性能,但在广泛的实验中仅占计算时间的3%。我们方法的可靠性在于,我们使用两个目标之间的边缘来评估对抗性示例的质量,这些目标可以精确地识别最对抗性的示例。我们方法的计算效率在于有效的顺序目标排名选择(星形)方法,以确保MM攻击的成本与类数无关。 MM攻击开辟了一种评估对抗性鲁棒性的新方法,并提供了一种可行且可靠的方式来生成高质量的对抗示例。
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数据隐私是可以感知环境,与人类交流并在现实世界中采取行动的体现代理的核心问题。在帮助人类完成任务的同时,代理商可以观察和处理用户的敏感信息,例如房屋环境,人类活动等。在这项工作中,我们介绍了隐私的体现的代理人学习,以实现视觉和语言导航的任务( VLN),其中一个体现的代理通过按照自然语言说明进行导航房屋环境。我们将每个房屋环境视为本地客户,除了与云服务器和其他客户端共享本地更新,并提出了一个新颖的联合视觉和语言导航(FIDVLN)框架,以保护培训和预培训期间的数据隐私勘探。特别是,我们提出了一种分散的培训策略,以将每个客户的数据限制在其本地模型培训中,并采用联合的预探测方法,以进行部分模型聚合,以改善模型的通用性,使其对看不见的环境。 R2R和RXR数据集的广泛结果表明,在我们的FEDVLN框架下,分散的VLN模型在集中式培训的同时,在保护可见的环境隐私的同时,取得了可比的结果,并且联合预探索明显超过了集中式预探测,同时保留了不见了的环境隐私。
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非政策评估和学习(OPE/L)使用离线观察数据来做出更好的决策,这对于在线实验有限的应用至关重要。但是,完全取决于记录的数据,OPE/L对环境分布的变化很敏感 - 数据生成环境和部署策略的差异。 \ citet {si2020distributional}提议的分布在稳健的OPE/L(Drope/L)解决此问题,但该提案依赖于逆向权重,如果估计错误和遗憾,如果倾向是非参数估计的,即使其差异是次级估计,即使是次级估计的,其估计错误和遗憾将降低。对于标准的,非体,OPE/L,这是通过双重鲁棒(DR)方法来解决的,但它们并不自然地扩展到更复杂的drop/l,涉及最糟糕的期望。在本文中,我们提出了具有KL-Divergence不确定性集的DROPE/L的第一个DR算法。为了进行评估,我们提出了局部双重稳健的drope(LDR $^2 $ ope),并表明它在弱产品速率条件下实现了半摩托效率。多亏了本地化技术,LDR $^2 $ OPE仅需要安装少量回归,就像标准OPE的DR方法一样。为了学习,我们提出了连续的双重稳健下降(CDR $^2 $ opl),并表明,在涉及连续回归的产品速率条件下,它具有$ \ Mathcal {o} \ left的快速后悔率(n^) {-1/2} \ right)$即使未知的倾向是非参数估计的。我们从经验上验证了模拟中的算法,并将结果进一步扩展到一般$ f $ divergence的不确定性集。
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We present a neural flow wavefunction, Gauge-Fermion FlowNet, and use it to simulate 2+1D lattice compact quantum electrodynamics with finite density dynamical fermions. The gauge field is represented by a neural network which parameterizes a discretized flow-based transformation of the amplitude while the fermionic sign structure is represented by a neural net backflow. This approach directly represents the $U(1)$ degree of freedom without any truncation, obeys Guass's law by construction, samples autoregressively avoiding any equilibration time, and variationally simulates Gauge-Fermion systems with sign problems accurately. In this model, we investigate confinement and string breaking phenomena in different fermion density and hopping regimes. We study the phase transition from the charge crystal phase to the vacuum phase at zero density, and observe the phase seperation and the net charge penetration blocking effect under magnetic interaction at finite density. In addition, we investigate a magnetic phase transition due to the competition effect between the kinetic energy of fermions and the magnetic energy of the gauge field. With our method, we further note potential differences on the order of the phase transitions between a continuous $U(1)$ system and one with finite truncation. Our state-of-the-art neural network approach opens up new possibilities to study different gauge theories coupled to dynamical matter in higher dimensions.
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Most multimodal multi-objective evolutionary algorithms (MMEAs) aim to find all global Pareto optimal sets (PSs) for a multimodal multi-objective optimization problem (MMOP). However, in real-world problems, decision makers (DMs) may be also interested in local PSs. Also, searching for both global and local PSs is more general in view of dealing with MMOPs, which can be seen as a generalized MMOP. In addition, the state-of-the-art MMEAs exhibit poor convergence on high-dimension MMOPs. To address the above two issues, in this study, a novel coevolutionary framework termed CoMMEA for multimodal multi-objective optimization is proposed to better obtain both global and local PSs, and simultaneously, to improve the convergence performance in dealing with high-dimension MMOPs. Specifically, the CoMMEA introduces two archives to the search process, and coevolves them simultaneously through effective knowledge transfer. The convergence archive assists the CoMMEA to quickly approaching the Pareto optimal front (PF). The knowledge of the converged solutions is then transferred to the diversity archive which utilizes the local convergence indicator and the $\epsilon$-dominance-based method to obtain global and local PSs effectively. Experimental results show that CoMMEA is competitive compared to seven state-of-the-art MMEAs on fifty-four complex MMOPs.
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Objective: Thigh muscle group segmentation is important for assessment of muscle anatomy, metabolic disease and aging. Many efforts have been put into quantifying muscle tissues with magnetic resonance (MR) imaging including manual annotation of individual muscles. However, leveraging publicly available annotations in MR images to achieve muscle group segmentation on single slice computed tomography (CT) thigh images is challenging. Method: We propose an unsupervised domain adaptation pipeline with self-training to transfer labels from 3D MR to single CT slice. First, we transform the image appearance from MR to CT with CycleGAN and feed the synthesized CT images to a segmenter simultaneously. Single CT slices are divided into hard and easy cohorts based on the entropy of pseudo labels inferenced by the segmenter. After refining easy cohort pseudo labels based on anatomical assumption, self-training with easy and hard splits is applied to fine tune the segmenter. Results: On 152 withheld single CT thigh images, the proposed pipeline achieved a mean Dice of 0.888(0.041) across all muscle groups including sartorius, hamstrings, quadriceps femoris and gracilis. muscles Conclusion: To our best knowledge, this is the first pipeline to achieve thigh imaging domain adaptation from MR to CT. The proposed pipeline is effective and robust in extracting muscle groups on 2D single slice CT thigh images.The container is available for public use at https://github.com/MASILab/DA_CT_muscle_seg
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