Due to the partial observability and communication constraints in many multiagent reinforcement learning (MARL) tasks, centralized training with decentralized execution (CTDE) has become one of the most widely used MARL paradigms. In CTDE, centralized information is dedicated to learning the allocation of the team reward with a mixing network while the learning of individualQ-values is usually based on local observations. The insufficient utility of global observation will degrade performance in challenging environments. To this end, this work proposes a novel Centralized Teacher with a Decentralized Student (CTDS) framework, which consists of a teacher model and a student model. Specifically, the teacher model allocates the team reward by learning individualQ-values conditioned on global observation while the student model utilizes the partial observations to approximate theQ-values estimated by the teacher model. In this way, CTDS balances the full utilization of global observation during training and the feasibility of decentralized execution for online inference. Our CTDS framework is generic, which is ready to be applied upon existing CTDE methods to boost their performance. We conduct experiments on a challenging set ofStarCraft IImicromanagement tasks to test the effectiveness of our method and the results show that CTDS outperforms the existing value-based MARL methods.

Image distortion during wireless transmission presents a significant challenge for real-world artificial intelligence (AI) applications. Recent methods have attempted to address this issue by integrating neural networks into the wireless transmission system. However, these approaches often require a large volume of labeled training data, which can be expensive and time-consuming to collect. To address this issue, we propose a novel approach,Self-SupervisedMulti-AgentFeedbackEnabledNeuralNetworks (S2MAFENN). S2MAFENN is designed to improve the efficiency of labeled data in wireless image transmission. It incorporates a Feedbacker agent that emulates the error correction mechanisms observed in primate brains and employs self-supervised contrastive learning to extract representations from unlabeled distorted images independently. From a theoretical perspective, we model the training process of S2MAFENN as a three-player Stackelberg game and provide evidence that S2MAFENN can achieve exponential convergence rates. We then empirically validate our approach by assessing the representations learned through S2MAFENN. We use varied labeled CIFAR10 and CIFAR100 data to simulate real image transmissions over the Rayleigh fading and 5G channels. Our results show that S2MAFENN matches or even surpasses the performance of state-of-the-art self-supervised training methods, even when only 50% of labels are used. Moreover, S2MAFENN yields average accuracy gains of 5.11%, 5.8%, and 4.58% with only 0.1, 0.2, and 0.5 of the labels transmitted over the 5G channel, respectively. For the downstream task of semantic segmentation over the 5G channel, S2MAFENN exhibits significant advancements on the ADE20K dataset. It achieves enhancements of approximately 7% and 8.7% in Mean IoU and DICE metrics, respectively, surpassing the performance of current state-of-the-art methods.

Reward shaping (RS) is a powerful method in reinforcement learning (RL) for overcoming the problem of sparse or uninformative rewards. However, RS typically relies on manually engineered shaping-reward functions whose construc- tion is time-consuming and error-prone. It also requires domain knowledge which runs contrary to the goal of autonomous learning. We introduce Reinforcement Learning Optimising Shaping Algorithm (ROSA), an automated reward shaping framework in which the shaping-reward function is constructed in a Markov game between two agents. A reward-shaping agent (Shaper) uses switching controls to determine which states to add shaping rewards for more efficient learning while the other agent (Controller) learns the optimal policy for the task using these shaped rewards. We prove that ROSA, which adopts existing RL algorithms, learns to construct a shaping-reward function that is beneficial to the task thus ensuring efficient convergence to high performance policies. We demonstrate ROSA’s properties in three didactic experiments and show its superior performance against state-of-the-art RS algorithms in challenging sparse reward environments.

Cooperative multi-agent reinforcement learning (MARL) has made prominent progress in recent years. For training efficiency and scalability, most of the MARL algorithms make all agents share the same policy or value network. However, in many complex multi-agent tasks, different agents are expected to possess specific abilities to handle different subtasks. In those scenarios, sharing parameters indiscriminately may lead to similar behavior across all agents, which will limit the exploration efficiency and degrade the final performance. To balance the training complexity and the diversity of agent behavior, we propose a novel framework to learn dynamic subtask assignment (LDSA) in cooperative MARL. Specifically, we first introduce a subtask encoder to construct a vector representation for each subtask according to its identity. To reasonably assign agents to different subtasks, we propose an ability-based subtask selection strategy, which can dynamically group agents with similar abilities into the same subtask. In this way, agents dealing with the same subtask share their learning of specific abilities and different subtasks correspond to different specific abilities. We further introduce two regularizers to increase the representation difference between subtasks and stabilize the training by discouraging agents from frequently changing subtasks, respectively. Empirical results show that LDSA learns reasonable and effective subtask assignment for better collaboration and significantly improves the learning performance on the challenging StarCraft II micromanagement benchmark and Google Research Football.

This paper proposes a hierarchical decision-making and control algorithm for the shepherd game, the seventh mission in the International Aerial Robotics Competition (IARC). In this game, the agent (a multirotor aerial robot) is required to contact targets (ground vehicles) sequentially and drive them to a certain boundary to earn score. During the game of 10 min, the agent should be fully autonomous without any human interference. Regarding the lower-level controller and dynamics of the agent, each action takes a duration of time to accomplish. Denoted as an action delay, in this paper, this action duration is nonconstant and is related to the final reward. Therefore, the challenging point is making the agent "aware of time" when applying a certain action. We solve this problem by two approaches: deep Q-networks and lookup table. The action delay predictor in the decision-level is fitted by a lower-level controller. Through simulations by the example of the shepherd game, the effectiveness and efficiency of this approach are validated. This paper helps our team winning the first prize in IARC 2017, and keeps the best record of this mission since it was released in 2013.

For a multirotor micro aerial vehicle (MAV) flying in the outdoor environment, its downside hemisphere has richest visual information. All that information can be obtained by a single fisheye camera with larger than 180 degrees field of view (FOV). Traditionally, the unrestored fisheye image is restored to a flat image before subsequent processing, which is both resource and time consuming. In this paper, to save resource and time, a method of fisheye object detection and localization on the unrestored fisheye image is proposed. A single-stage neural network is built for object detection. To improve the performance of detector, its submodules are designed specifically by combining the central rotational property and severe distortion of the fisheye image. To meet the real-time requirements of onboard computation, the detector is also tuned to be light-weight. After that, the detected objects are localized with assistance of by a data fusion on the fisheye model and MAV sensory data (altitude, attitude, etc.), The experimental results have validated the effectiveness of the proposed methods in this paper.