联邦学习(FL)是一种分散的方法,使医院能够在不共享私人患者数据进行培训的情况下协作学习模型。在FL中,参与者医院定期交换培训结果,而不是使用中央服务器培训样品。但是,访问模型参数或梯度可以暴露私人培训数据样本。为了应对这一挑战,我们采用安全的多方计算(SMC)来建立一个保护隐私的联合学习框架。在我们提出的方法中,医院分为集群。在当地培训之后,每家医院在同一集群中分解了其他医院的模型权重,因此没有一家医院可以自己检索其他医院的体重。然后,所有医院总结了收到的权重,将结果发送到中央服务器。最后,中央服务器汇总了结果,检索模型的平均权重并更新模型,而无需访问各个医院的权重。我们在公开可用的存储库《癌症基因组图集》(TCGA)上进行实验。我们将提议框架的性能与差异隐私进行比较,并将平均为基准。结果表明,与差异隐私相比,我们的框架可以实现更高的准确性,而没有隐私泄漏风险,而较高的通信开销则可以实现。
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我们分析了含有100,000个补丁的结直肠癌(CRC)组织病理学数据集的离线和在线三胞胎挖掘的效果。我们认为在线和离线采矿中,极端,即与给定锚的最远和最近的补丁。尽管许多工作仅着眼于在线选择三胞胎(批次),但我们还研究了以离线方式训练之前的极端距离和邻居补丁的效果。我们分析了极端案例的嵌入离线距离与在线采矿的影响,包括易于正面的,批处理半硬度,批处理硬线挖掘,邻里组件分析损失,其代理版本和距离加权采样。我们还根据极端距离进行了在线方法,并根据数据模式进行了全面比较离线和在线挖掘绩效,并将离线挖掘解释为具有大型迷你批量大小的在线挖掘的可拖延概括。同样,我们讨论了不同结直肠组织类型的关系。我们发现,离线和在线挖掘方法在本研究中具有可比的特定体系结构(例如RESNET-18)具有可比性的性能。此外,我们发现包括不同的极端距离在内的各种情况是有希望的,尤其是在在线方法中。
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In this paper, we present a novel control architecture for the online adaptation of bipedal locomotion on inclined obstacles. In particular, we introduce a novel, cost-effective, and versatile foot sensor to detect the proximity of the robot's feet to the ground (bump sensor). By employing this sensor, feedback controllers are implemented to reduce the impact forces during the transition of the swing to stance phase or steeping on inclined unseen obstacles. Compared to conventional sensors based on contact reaction force, this sensor detects the distance to the ground or obstacles before the foot touches the obstacle and therefore provides predictive information to anticipate the obstacles. The controller of the proposed bump sensor interacts with another admittance controller to adjust leg length. The walking experiments show successful locomotion on the unseen inclined obstacle without reducing the locomotion speed with a slope angle of 12. Foot position error causes a hard impact with the ground as a consequence of accumulative error caused by links and connections' deflection (which is manufactured by university tools). The proposed framework drastically reduces the feet' impact with the ground.
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Recent advances in distributed artificial intelligence (AI) have led to tremendous breakthroughs in various communication services, from fault-tolerant factory automation to smart cities. When distributed learning is run over a set of wirelessly connected devices, random channel fluctuations and the incumbent services running on the same network impact the performance of both distributed learning and the coexisting service. In this paper, we investigate a mixed service scenario where distributed AI workflow and ultra-reliable low latency communication (URLLC) services run concurrently over a network. Consequently, we propose a risk sensitivity-based formulation for device selection to minimize the AI training delays during its convergence period while ensuring that the operational requirements of the URLLC service are met. To address this challenging coexistence problem, we transform it into a deep reinforcement learning problem and address it via a framework based on soft actor-critic algorithm. We evaluate our solution with a realistic and 3GPP-compliant simulator for factory automation use cases. Our simulation results confirm that our solution can significantly decrease the training delay of the distributed AI service while keeping the URLLC availability above its required threshold and close to the scenario where URLLC solely consumes all network resources.
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The behavior of the network and its stability are governed by both dynamics of individual nodes as well as their topological interconnections. Attention mechanism as an integral part of neural network models was initially designed for natural language processing (NLP), and so far, has shown excellent performance in combining dynamics of individual nodes and the coupling strengths between them within a network. Despite undoubted impact of attention mechanism, it is not yet clear why some nodes of a network get higher attention weights. To come up with more explainable solutions, we tried to look at the problem from stability perspective. Based on stability theory, negative connections in a network can create feedback loops or other complex structures by allowing information to flow in the opposite direction. These structures play a critical role in the dynamics of a complex system and can contribute to abnormal synchronization, amplification, or suppression. We hypothesized that those nodes that are involved in organizing such structures can push the entire network into instability modes and therefore need higher attention during analysis. To test this hypothesis, attention mechanism along with spectral and topological stability analyses was performed on a real-world numerical problem, i.e., a linear Multi Input Multi Output state-space model of a piezoelectric tube actuator. The findings of our study suggest that the attention should be directed toward the collective behaviour of imbalanced structures and polarity-driven structural instabilities within the network. The results demonstrated that the nodes receiving more attention cause more instability in the system. Our study provides a proof of concept to understand why perturbing some nodes of a network may cause dramatic changes in the network dynamics.
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We introduce a new probabilistic temporal logic for the verification of Markov Decision Processes (MDP). Our logic is the first to include operators for causal reasoning, allowing us to express interventional and counterfactual queries. Given a path formula $\phi$, an interventional property is concerned with the satisfaction probability of $\phi$ if we apply a particular change $I$ to the MDP (e.g., switching to a different policy); a counterfactual allows us to compute, given an observed MDP path $\tau$, what the outcome of $\phi$ would have been had we applied $I$ in the past. For its ability to reason about different configurations of the MDP, our approach represents a departure from existing probabilistic temporal logics that can only reason about a fixed system configuration. From a syntactic viewpoint, we introduce a generalized counterfactual operator that subsumes both interventional and counterfactual probabilities as well as the traditional probabilistic operator found in e.g., PCTL. From a semantics viewpoint, our logic is interpreted over a structural causal model (SCM) translation of the MDP, which gives us a representation amenable to counterfactual reasoning. We provide a proof-of-concept evaluation of our logic on a reach-avoid task in a grid-world model.
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Although deep networks have shown vulnerability to evasion attacks, such attacks have usually unrealistic requirements. Recent literature discussed the possibility to remove or not some of these requirements. This paper contributes to this literature by introducing a carpet-bombing patch attack which has almost no requirement. Targeting the feature representations, this patch attack does not require knowing the network task. This attack decreases accuracy on Imagenet, mAP on Pascal Voc, and IoU on Cityscapes without being aware that the underlying tasks involved classification, detection or semantic segmentation, respectively. Beyond the potential safety issues raised by this attack, the impact of the carpet-bombing attack highlights some interesting property of deep network layer dynamic.
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This work addresses fair generative models. Dataset biases have been a major cause of unfairness in deep generative models. Previous work had proposed to augment large, biased datasets with small, unbiased reference datasets. Under this setup, a weakly-supervised approach has been proposed, which achieves state-of-the-art quality and fairness in generated samples. In our work, based on this setup, we propose a simple yet effective approach. Specifically, first, we propose fairTL, a transfer learning approach to learn fair generative models. Under fairTL, we pre-train the generative model with the available large, biased datasets and subsequently adapt the model using the small, unbiased reference dataset. We find that our fairTL can learn expressive sample generation during pre-training, thanks to the large (biased) dataset. This knowledge is then transferred to the target model during adaptation, which also learns to capture the underlying fair distribution of the small reference dataset. Second, we propose fairTL++, where we introduce two additional innovations to improve upon fairTL: (i) multiple feedback and (ii) Linear-Probing followed by Fine-Tuning (LP-FT). Taking one step further, we consider an alternative, challenging setup when only a pre-trained (potentially biased) model is available but the dataset that was used to pre-train the model is inaccessible. We demonstrate that our proposed fairTL and fairTL++ remain very effective under this setup. We note that previous work requires access to the large, biased datasets and is incapable of handling this more challenging setup. Extensive experiments show that fairTL and fairTL++ achieve state-of-the-art in both quality and fairness of generated samples. The code and additional resources can be found at bearwithchris.github.io/fairTL/.
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Many existing datasets for lidar place recognition are solely representative of structured urban environments, and have recently been saturated in performance by deep learning based approaches. Natural and unstructured environments present many additional challenges for the tasks of long-term localisation but these environments are not represented in currently available datasets. To address this we introduce Wild-Places, a challenging large-scale dataset for lidar place recognition in unstructured, natural environments. Wild-Places contains eight lidar sequences collected with a handheld sensor payload over the course of fourteen months, containing a total of 67K undistorted lidar submaps along with accurate 6DoF ground truth. Our dataset contains multiple revisits both within and between sequences, allowing for both intra-sequence (i.e. loop closure detection) and inter-sequence (i.e. re-localisation) place recognition. We also benchmark several state-of-the-art approaches to demonstrate the challenges that this dataset introduces, particularly the case of long-term place recognition due to natural environments changing over time. Our dataset and code will be available at https://csiro-robotics.github.io/Wild-Places.
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检测和避免(DAA)功能对于无人飞机系统(UAS)的安全操作至关重要。本文介绍了Airtrack,这是一个仅实时视觉检测和跟踪框架,尊重SUAS系统的大小,重量和功率(交换)约束。鉴于遥远飞机的低信噪比(SNR),我们建议在深度学习框架中使用完整的分辨率图像,以对齐连续的图像以消除自我动态。然后,对齐的图像在级联的初级和次级分类器中下游使用,以改善多个指标的检测和跟踪性能。我们表明,Airtrack在亚马逊机载对象跟踪(AOT)数据集上胜过最先进的基线。多次现实世界的飞行测试与CESSNA 172与通用航空交通相互作用,并在受控的设置中朝着UAS飞向UAS的其他近碰撞飞行测试,该拟议方法满足了新引入的ASTM F3442/F3442M标准DAA标准。经验评估表明,我们的系统的概率超过900m,范围超过95%。视频可在https://youtu.be/h3ll_wjxjpw上找到。
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