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Revisit Mixture Models for Multi-Agent Simulation: Experimental Study within a Unified Framework

arXiv.org Artificial Intelligence

Simulation plays a crucial role in assessing autonomous driving systems, where the generation of realistic multi-agent behaviors is a key aspect. In multi-agent simulation, the primary challenges include behavioral multimodality and closed-loop distributional shifts. In this study, we revisit mixture models for generating multimodal agent behaviors, which can cover the mainstream methods including continuous mixture models and GPT-like discrete models. Furthermore, we introduce a closed-loop sample generation approach tailored for mixture models to mitigate distributional shifts. Within the unified mixture model~(UniMM) framework, we recognize critical configurations from both model and data perspectives. We conduct a systematic examination of various model configurations, including positive component matching, continuous regression, prediction horizon, and the number of components. Moreover, our investigation into the data configuration highlights the pivotal role of closed-loop samples in achieving realistic simulations. To extend the benefits of closed-loop samples across a broader range of mixture models, we further address the shortcut learning and off-policy learning issues. Leveraging insights from our exploration, the distinct variants proposed within the UniMM framework, including discrete, anchor-free, and anchor-based models, all achieve state-of-the-art performance on the WOSAC benchmark.


Towards Open-Source and Modular Space Systems with ATMOS

arXiv.org Artificial Intelligence

Abstract--In the near future, autonomous space systems will compose a large number of the spacecraft being deployed. Their tasks will involve autonomous rendezvous and proximity operations with large structures, such as inspections or assembly of orbiting space stations and maintenance and human-assistance tasks over shared workspaces. To promote replicable and reliable scientific results for autonomous control of spacecraft, we present the design of a space systems laboratory based on open-source and modular software and hardware. The simulation software provides a software-in-the-loop (SITL) architecture that seamlessly transfers simulated results to the ATMOS platforms, developed for testing of multi-agent autonomy schemes for microgravity. The manuscript presents the KTH space systems laboratory facilities and the ATMOS platform as open-source hardware and software contributions. To the left, we see the tethers of the low-pressure compressor system. Software and hardware contributions can be found in: 1. PX4Space: Athens [6] proposed a similar test bed, where the platforms https://atmos.discower.io The facility also provides a vision-based I. This The space sector has experienced significant growth [1] in facility was recently upgraded to more modern avionics, motion the last decade, in part due to the decreased costs of access to capture ground-truth positioning, and robotics communication space through multiple commercial operators [2], but also due software through the Robotics Operating System (ROS) [7]. to the maturation of existing technologies and, consequently, Stanford University's Autonomous Systems Laboratory freeflyer reduced pricing of the deployed equipment. In the last twenty testbed [8], [9], [10] uses a similar, round platform as to thirty years, a few academic and industrial research facilities a free-flying robotic system for path planning, docking and have been created to test space systems by replicating motion capturing of space systems, paired with an open-source Python in microgravity on Earth.


Optimization and Learning in Open Multi-Agent Systems

arXiv.org Artificial Intelligence

Modern artificial intelligence relies on networks of agents that collect data, process information, and exchange it with neighbors to collaboratively solve optimization and learning problems. This article introduces a novel distributed algorithm to address a broad class of these problems in "open networks", where the number of participating agents may vary due to several factors, such as autonomous decisions, heterogeneous resource availability, or DoS attacks. Extending the current literature, the convergence analysis of the proposed algorithm is based on the newly developed "Theory of Open Operators", which characterizes an operator as open when the set of components to be updated changes over time, yielding to time-varying operators acting on sequences of points of different dimensions and compositions. The mathematical tools and convergence results developed here provide a general framework for evaluating distributed algorithms in open networks, allowing to characterize their performance in terms of the punctual distance from the optimal solution, in contrast with regret-based metrics that assess cumulative performance over a finite-time horizon. As illustrative examples, the proposed algorithm is used to solve dynamic consensus or tracking problems on different metrics of interest, such as average, median, and min/max value, as well as classification problems with logistic loss functions.


ToolFactory: Automating Tool Generation by Leveraging LLM to Understand REST API Documentations

arXiv.org Artificial Intelligence

LLM-based tool agents offer natural language interfaces, enabling users to seamlessly interact with computing services. While REST APIs are valuable resources for building such agents, they must first be transformed into AI-compatible tools. Automatically generating AI-compatible tools from REST API documents can greatly streamline tool agent development and minimize user learning curves. However, API documentation often suffers from a lack of standardization, inconsistent schemas, and incomplete information. To address these issues, we developed \textbf{ToolFactory}, an open-source pipeline for automating tool generation from unstructured API documents. To enhance the reliability of the developed tools, we implemented an evaluation method to diagnose errors. Furthermore, we built a knowledge base of verified tools, which we leveraged to infer missing information from poorly documented APIs. We developed the API Extraction Benchmark, comprising 167 API documents and 744 endpoints in various formats, and designed a JSON schema to annotate them. This annotated dataset was utilized to train and validate ToolFactory. The experimental results highlight the effectiveness of ToolFactory. We also demonstrated ToolFactory by creating a domain-specific AI agent for glycomaterials research. ToolFactory exhibits significant potential for facilitating the seamless integration of scientific REST APIs into AI workflows.


Learning Mean Field Control on Sparse Graphs

arXiv.org Artificial Intelligence

Large agent networks are abundant in applications and nature and pose difficult challenges in the field of multi-agent reinforcement learning (MARL) due to their computational and theoretical complexity. While graphon mean field games and their extensions provide efficient learning algorithms for dense and moderately sparse agent networks, the case of realistic sparser graphs remains largely unsolved. Thus, we propose a novel mean field control model inspired by local weak convergence to include sparse graphs such as power law networks with coefficients above two. Besides a theoretical analysis, we design scalable learning algorithms which apply to the challenging class of graph sequences with finite first moment. We compare our model and algorithms for various examples on synthetic and real world networks with mean field algorithms based on Lp graphons and graphexes. As it turns out, our approach outperforms existing methods in many examples and on various networks due to the special design aiming at an important, but so far hard to solve class of MARL problems.


Mobile-Agent-E: Self-Evolving Mobile Assistant for Complex Tasks

arXiv.org Artificial Intelligence

Smartphones have become indispensable in modern life, yet navigating complex tasks on mobile devices often remains frustrating. Recent advancements in large multimodal model (LMM)-based mobile agents have demonstrated the ability to perceive and act in mobile environments. However, current approaches face significant limitations: they fall short in addressing real-world human needs, struggle with reasoning-intensive and long-horizon tasks, and lack mechanisms to learn and improve from prior experiences. To overcome these challenges, we introduce Mobile-Agent-E, a hierarchical multi-agent framework capable of self-evolution through past experience. By hierarchical, we mean an explicit separation of high-level planning and low-level action execution. The framework comprises a Manager, responsible for devising overall plans by breaking down complex tasks into subgoals, and four subordinate agents--Perceptor, Operator, Action Reflector, and Notetaker--which handle fine-grained visual perception, immediate action execution, error verification, and information aggregation, respectively. Mobile-Agent-E also features a novel self-evolution module which maintains a persistent long-term memory comprising Tips and Shortcuts. Tips are general guidance and lessons learned from prior tasks on how to effectively interact with the environment. Shortcuts are reusable, executable sequences of atomic operations tailored for specific subroutines. The inclusion of Tips and Shortcuts facilitates continuous refinement in performance and efficiency. Alongside this framework, we introduce Mobile-Eval-E, a new benchmark featuring complex mobile tasks requiring long-horizon, multi-app interactions. Empirical results show that Mobile-Agent-E achieves a 22% absolute improvement over previous state-of-the-art approaches across three foundation model backbones. Project page: https://x-plug.github.io/MobileAgent.


Hierarchical Trajectory (Re)Planning for a Large Scale Swarm

arXiv.org Artificial Intelligence

We consider the trajectory replanning problem for a large-scale swarm in a cluttered environment. Our path planner replans for robots by utilizing a hierarchical approach, dividing the workspace, and computing collision-free paths for robots within each cell in parallel. Distributed trajectory optimization generates a deadlock-free trajectory for efficient execution and maintains the control feasibility even when the optimization fails. Our hierarchical approach combines the benefits of both centralized and decentralized methods, achieving a high task success rate while providing real-time replanning capability. Compared to decentralized approaches, our approach effectively avoids deadlocks and collisions, significantly increasing the task success rate. We demonstrate the real-time performance of our algorithm with up to 142 robots in simulation, and a representative 24 physical Crazyflie nano-quadrotor experiment.


Review for NeurIPS paper: Emergent Reciprocity and Team Formation from Randomized Uncertain Social Preferences

Neural Information Processing Systems

Four knowledgeable referees reviewed this paper. After conducting initial reviews, reading the authors' rebuttal (which resolved some concerns, but not the core concerns of two of the reviewers), and discussing the paper, the reviewers did not agree on an outcome. Two of the reviewers came to the conclusion that this is a ground-breaking paper (simple and elegant). The other two reviewers were perhaps somewhat intrigued, but did not feel the paper was yet ready for publication. For example, during the discussion phase, R4 (a very accomplished and well-respected research in the field) made very valid points about the papers weaknesses: "So all this leads me to suggest that there needs to be a better context, more related work and a better way to situate the paper in related arenas, e.g., provide some sort of a framework to back up the findings. I understand the issue of limited space, but given the amount of literature in this area, I feel that the paper doesnt do a good enough job explaining its findings in context."


Review for NeurIPS paper: Learning to Incentivize Other Learning Agents

Neural Information Processing Systems

Weaknesses: I have two concerns on (1) baselines and (2) scalability. IA is a good one and it is nice to see that LIO outperforms IA, but I do think the results can be more convincing if more benchmark algorithms can be included. Mutual information can be also viewed as an approximation of accounting other agents' future policy change and has shown great performances in harvest/cleanup with a large number of agents. Can we simply learn a value function conditioned on the received rewards of different agents (in the same spirit of DDPG) so that we can avoid performing second-order gradient? These are the questions raised when I read the paper and I believe a more in-depth discussion/experiments will further consolidate the contribution of this work.


Review for NeurIPS paper: Calibration of Shared Equilibria in General Sum Partially Observable Markov Games

Neural Information Processing Systems

Summary and Contributions: The paper presents the concept of shared equilibrium in certain kinds of multi agent stochastic games with a restricted form of partial observability. The formalism includes the notion of supertypes (different distributions of agents) and types (where each agents is given a true type each episode). The agent's type influences the rewards available as does the joint state of the system and joint action over all agents. One key constraint is that all agents of the same type follow the same policy from an egocentric perspective (where they themselves are the focal agent and all other agents are interchangeable). They define a policy gradient approach for individual agents, also present a higher order learning rule that shifts the distribution over supertypes at a slower timescale.