The automatic design of soft robots is an intertwined process of evolving morphology and learning control. As reinforcement learning is repeatedly used to learn the control policy for each candidate robot design, the design process becomes time-consuming. So far, the common design paradigm in robotics has been based on a single task. In fact, there is control similarity between different tasks. Learning a controller with combinatorial generalization capabilities across a variety of tasks can significantly reduce the computational cost of the design process. To this end, we propose a cross-task collaborative evolutionary algorithm that constructs a universal controller capable of solving a group of tasks simultaneously. Instead of “one robot, one controller, one task" paradigm, the proposed universal controller is to learn a control policy, which can generalize to unseen morphologies. After the controller learning on easy tasks, the universal controller can be further transferred to new hard tasks. Furthermore, the knowledge transfer is incorporated in the search strategy to enhance the performance of the universal controller. The experimental results on 13 test tasks demonstrate that the proposed algorithm outperforms the SOTA design algorithms on 8 of them. Compared to these algorithms, the proposed algorithm reduces the computational cost by 55% while achieving comparable performance, particularly for unseen hard tasks.

Soft robot design is an intricate field with unique challenges due to its complex and vast search space. In the past literature, evolutionary computation algorithms, including novel probabilistic generative models (PGMs), have shown potential in this realm. However, these methods are sample inefficient and predominantly focus on rigid robots in locomotion tasks, which limit their performance and application in robot design automation. In this work, we propose MorphVAE, an innovative PGM that incorporates a multi-task training scheme and a meticulously crafted sampling technique termed ``continuous natural selection'', aimed at bolstering sample efficiency. This method empowers us to gain insights from assessed samples across diverse tasks and temporal evolutionary stages, while simultaneously maintaining a delicate balance between optimization efficiency and biodiversity. Through extensive experiments in various locomotion and manipulation tasks, we substantiate the efficiency of MorphVAE in generating high-performing and diverse designs, surpassing the performance of competitive baselines.

In the field of robotic control, designing individual controllers for each robot leads to high computational costs. Universal control policies, applicable across diverse robot morphologies, promise to mitigate this challenge. Predominantly, models based on Graph Neural Networks (GNN) and Transformers are employed, owing to their effectiveness in capturing relational dynamics across a robot’s limbs. However, these models typically employ homogeneous graph structures that overlook the functional diversity of different limbs. To bridge this gap, we introduce HeteroMorpheus, a novel method based on heterogeneous graph Transformer. This method uniquely addresses limb heterogeneity, fostering better representation of robot dynamics of various morphologies. Through extensive experiments we demonstrate the superiority of HeteroMorpheus against state-of-the-art methods in the capability of policy generalization, including zero-shot generalization and sample-efficient transfer to unfamiliar robot morphologies.

The automatic design of soft robots characterizes as jointly optimizing structure and control. As reinforcement learning is gradually used to optimize control, the time-consuming controller training makes soft robots design an expensive optimization problem. Although surrogate-assisted evolutionary algorithms have made a remarkable achievement in dealing with expensive optimization problems, they typically suffer from challenges in constructing accurate surrogate models due to the complex mapping among structure, control, and task performance. Therefore, we propose an action inheritance-based evolutionary algorithm to accelerate the design process. Instead of training a controller, the proposed algorithm uses inherited actions to control a candidate design to complete a task and obtain its approximated performance. Inherited actions are near-optimal control policies that are partially or entirely inherited from optimized control actions of a real evaluated robot design. The action inheritance plays the role of surrogate models where its input is the structure and output is the near-optimal control actions. We also propose a random perturbation operation to estimate the error introduced by inherited control actions. The effectiveness of our proposed method is validated by evaluating it on a wide range of tasks, including locomotion and manipulation. Experimental results show that our algorithm is better than the other three state-of-the-art algorithms on most tasks when only a limited computational budget is available. Compared with the algorithm without surrogate models, our algorithm saves about half the computing cost.

There is an emerging trend in the Chinese automobile industries that automakers are introducing exclusive enterprise social networks (EESNs) to expand sales and provide after-sale services. The traditional online social networks (OSNs) and enterprise social networks (ESNs), such as X (formerly known as Twitter) and Yammer, are ingeniously designed to facilitate unregulated communications among equal individuals. However, users in EESNs are naturally social stratified, consisting of both enterprise staffs and customers. In addition, the motivation to operate EESNs can be quite complicated, including providing customer services and facilitating communication among enterprise staffs. As a result, the social behaviors in EESNs can be quite different from those in OSNs and ESNs. In this work, we aim to analyze the social behaviors in EESNs. We consider the Chinese car manufacturer NIO as a typical example of EESNs and provide the following contributions. First, we formulate the social behavior analysis in EESNs as a link prediction problem in heterogeneous social networks. Second, to analyze this link prediction problem, we derive plentiful user features and build multiple meta-path graphs for EESNs. Third, we develop a novel Fast (H)eterogeneous graph (A)ttention (N)etwork algorithm for (D)irected graphs (FastHAND) to predict directed social links among users in EESNs. This algorithm introduces feature group attention at the node-level and uses an edge sampling algorithm over directed meta-path graphs to reduce the computation cost. By conducting various experiments on the NIO community data, we demonstrate the predictive power of our proposed FastHAND method. The experimental results also verify our intuitions about social affinity propagation in EESNs.

Hierarchical text classification (HTC) is a challenging task, in which the labels of texts can be organized into a category hierarchy.To deal with the HTC problem, many existing works focus on utilizing the parent-child relationships that are explicitly shown in the hierarchy.However, texts with a category hierarchy also have some latent relevancy among labels in the same level of the hierarchy.We refer to these labels as peer labels, from which the peer effects are originally utilized in our work to improve the classification performance.To fully explore the peer-label relationship, we develop a PeerHTC method.This method innovatively measures the latent relevancy of peer labels through several metrics and then encodes the relevancy with a Graph Convolutional Neural Network.We also propose a sample importance learning method to ameliorate the side effects raised by modelling the peer label relevancy.Our experiments on several standard datasets demonstrate the evidence of peer labels and the superiority of PeerHTC over other state-of-the-art HTC methods in terms of classification accuracy.

Most existing adversarial attack methods against detectors involve adding adversarial perturbations to benign images to synthesiz adversarial examples. However, directly applying these methods, originally designed for natural image detectors, to optical aerial image detectors can lead to perturbations that appear unnatural and suspicious to human eyes, owing to intrinsic dissimilarities between these two types of images. Inspired by the fact that the captured optical aerial images are heavily affected by weather conditions, this paper proposes a novel method for conducting adversarial attacks against optical aerial detectors by leveraging natural weather-style perturbations. Compared to existing methods, our scheme produces more natural and stealthy adversarial examples. To enhance the practicality of the proposed method in real-world scenarios, we implement the attacks in black-box settings where only the model’s predictions are accessible. Specifically, we formulate the generation of adversarial weather perturbations in black-box as an optimization problem and effectively solve it using the Differential Evolution (DE) algorithm. Through extensive experiments, we verify the effectiveness of our method and investigate the transferability of generated adversarial examples across different models. In light of the significant generalization and effectiveness of our method, we generate and release the first dataset with adversarial weather-style perturbations based on the DOTA dataset, which we abbreviate as DOTA-W. This dataset serves as a valuable resource for evaluating and improving the robustness of optical aerial detectors. The code and dataset have been released at https://github.com/tang-agui/attADs-AWP.