GenAI4ELab/papercli-papers huggingface dataset:
Learning Fair Cooperation in Mixed-Motive Games with Indirect Reciprocity
Authors: Martin Smit; Fernando P. Santos
Venue: IJCAI 2024 (main)

Abstract: Altruistic cooperation is costly yet socially desirable. As a result, agents struggle to learn cooperative policies through independent reinforcement learning (RL). Indirect reciprocity, where agents consider their interaction partner’s reputation, has been shown to stabilise cooperation in homogeneous, idealised populations. However, more realistic settings are comprised of heterogeneous agents with different characteristics and group-based social identities. We study cooperation when agents are stratified into two such groups, and allow reputation updates and actions to depend on group information. We consider two modelling approaches: evolutionary game theory, where we comprehensively search for social norms (i.e., rules to assign reputations) leading to cooperation and fairness; and RL, where we consider how the stochastic dynamics of policy learning affects the analytically identified equilibria. We observe that a defecting majority leads the minority group to defect, but not the inverse. Moreover, changing the norms that judge inand out-group interactions can steer a system towards either fair or unfair cooperation. This is made clearer when moving beyond equilibrium analysis to independent RL agents, where convergence to fair cooperation occurs with a narrower set of norms. Our results highlight that, in heterogeneous populations with reputations, carefully defining interaction norms is fundamental to tackle both dilemmas of cooperation and of fairness.
Cooperation and Control in Delegation Games
Authors: Oliver Sourbut; Lewis Hammond; Harriet Wood
Venue: IJCAI 2024 (main)

Abstract: Many settings of interest involving humans and machines – from virtual personal assistants to autonomous vehicles – can naturally be modelled as principals (humans) delegating to agents (machines), which then interact with each other on their principals’ behalf. We refer to these multi-principal, multi-agent scenarios as delegation games. In such games, there are two important failure modes: problems of control (where an agent fails to act in line their principal’s preferences) and problems of cooperation (where the agents fail to work well together). In this paper we formalise and analyse these problems, further breaking them down into issues of alignment (do the players have similar preferences?) and capabilities (how competent are the players at satisfying those preferences?). We show – theoretically and empirically – how these measures determine the principals’ welfare, how they can be estimated using limited observations, and thus how they might be used to help us design more aligned and cooperative AI systems.
Faster Optimal Coalition Structure Generation via Offline Coalition Selection and Graph-Based Search
Authors: Redha Taguelmimt; Samir Aknine; Djamila Boukredera; Narayan Changder; Tuomas Sandholm
Venue: IJCAI 2024 (main)

Abstract: Coalition formation is a key capability in multi-agent systems. An important problem in coalition formation is coalition structure generation: partitioning agents into coalitions to optimize the social welfare. This is a challenging problem that has been the subject of active research for the past three decades. In this paper, we present a novel algorithm, SMART, for the problem based on a hybridization of three innovative techniques. Two of these techniques are based on dynamic programming, where we show a powerful connection between the coalitions selected for evaluation and the performance of the algorithms. These algorithms use offline phases to optimize the choice of coalitions to evaluate. The third one uses branch-and-bound and integer partition graph search to explore the solution space. Our techniques bring a new way of approaching the problem and a new level of precision to the field. In experiments over several common value distributions, we show that the hybridization of these techniques in SMART is faster than the fastest prior algorithms (ODP-IP, BOSS) in generating optimal solutions across all the value distributions.
MGCBS: An Optimal and Efficient Algorithm for Solving Multi-Goal Multi-Agent Path Finding Problem
Authors: Mingkai Tang; Yuanhang Li; Hongji Liu; Yingbing Chen; Ming Liu; Lujia Wang
Venue: IJCAI 2024 (main)

Abstract: With the expansion of the scale of robotics applications, the multi-goal multi-agent pathfinding (MG-MAPF) problem began to gain widespread attention. This problem requires each agent to visit pre-assigned multiple goal points at least once without conflict. Some previous methods have been proposed to solve the MG-MAPF problem based on Decoupling the goal Vertex visiting order search and the Single-agent pathfinding (DVS). However, this paper demonstrates that the methods based on DVS cannot always obtain the optimal solution. To obtain the optimal result, we propose the Multi-Goal Conflict-Based Search (MGCBS), which is based on Decoupling the goal Safe interval visiting order search and the Single-agent pathfinding (DSS). Additionally, we present the Time-Interval-Space Forest (TIS Forest) to enhance the efficiency of MGCBS by maintaining the shortest paths from any start point at any start time step to each safe interval at the goal points. The experiment demonstrates that our method can consistently obtain optimal results and execute up to 7 times faster than the state-of-the-art method in our evaluation.
Design a Win-Win Strategy That Is Fair to Both Service Providers and Tasks When Rejection Is Not an Option
Authors: Yohai Trabelsi; Pan Xu; Sarit Kraus
Venue: IJCAI 2024 (main)

Abstract: Assigning tasks to service providers is a frequent procedure across various applications. Often the tasks arrive dynamically while the service providers remain static. Preventing task rejection caused by service provider overload is of utmost significance. To ensure a positive experience in relevant applications for both service providers and tasks, fairness must be considered. To address the issue, we model the problem as an online matching within a bipartite graph and tackle two minimax problems: one focuses on minimizing the highest waiting time of a task, while the other aims to minimize the highest workload of a service provider. We show that the second problem can be expressed as a linear program and thus solved efficiently while maintaining a reasonable approximation to the objective of the first problem. We developed novel methods that utilize the two minimax problems. We conducted extensive simulation experiments using real data and demonstrated that our novel heuristics, based on the linear program, performed remarkably well.
Reinforcement Nash Equilibrium Solver
Authors: Xinrun Wang; Chang Yang; Shuxin Li; Pengdeng Li; Xiao Huang; Hau Chan; Bo An
Venue: IJCAI 2024 (main)

Abstract: Nash Equilibrium (NE) is the canonical solution concept of game theory, which provides an elegant tool to understand the rationalities. Though mixed strategy NE exists in any game with finite players and actions, computing NE in two- or multi-player general-sum games is PPAD-Complete. Various alternative solutions, e.g., Correlated Equilibrium (CE), and learning methods, e.g., fictitious play (FP), are proposed to approximate NE. For convenience, we call these methods as ``inexact solvers'', or ``solvers'' for short. However, the alternative solutions differ from NE and the learning methods generally fail to converge to NE. Therefore, in this work, we propose REinforcement Nash Equilibrium Solver (RENES), which trains a single policy to modify the games with different sizes and applies the solvers on the modified games where the obtained solution is evaluated on the original games. Specifically, our contributions are threefold. i) We represent the games as alpha-rank response graphs and leverage graph neural network (GNN) to handle the games with different sizes as inputs; ii) We use tensor decomposition, e.g., canonical polyadic (CP), to make the dimension of modifying actions fixed for games with different sizes; iii) We train the modifying strategy for games with the widely-used proximal policy optimization (PPO) and apply the solvers to solve the modified games, where the obtained solution is evaluated on original games. Extensive experiments on large-scale normal-form games show that our method can further improve the approximation of NE of different solvers, i.e., alpha-rank, CE, FP and PRD, and can be generalized to unseen games.
A Successful Strategy for Multichannel Iterated Prisoner’s Dilemma
Authors: Zhen Wang; Zhaoheng Cao; Juan Shi; Peican Zhu; Shuyue Hu; Chen Chu
Venue: IJCAI 2024 (main)

Abstract: Iterated prisoner’s dilemma (IPD) and its variants are fundamental models for understanding the evolution of cooperation in human society as well as AI systems. In this paper, we focus on multichannel IPD, and examine how an agent should behave to obtain generally high payoffs under this setting. We propose a novel strategy that chooses to cooperate or defect by considering the difference in the cumulative number of defections between two agents. We show that our proposed strategy is nice, retaliatory, and forgiving. Moreover, we analyze the performance of our proposed strategy across different scenarios, including the self-play settings with and without errors, as well as when facing various opponent strategies. In particular, we show that our proposed strategy is invincible and never loses to any opponent strategy in terms of the expected payoff. Last but not least, we empirically validate the evolutionary advantage of our strategy, and demonstrate its potential to serve as a catalyst for cooperation emergence.
Population-Based Diverse Exploration for Sparse-Reward Multi-Agent Tasks
Authors: Pei Xu; Junge Zhang; Kaiqi Huang
Venue: IJCAI 2024 (main)

Abstract: Exploration under sparse rewards is a key challenge for multi-agent reinforcement learning problems. Although population-based learning shows its potential in producing diverse behaviors, most previous works still focus on improving the exploration of a single joint policy. In this paper, we show that with a suitable exploration method, maintaining a population of joint policies rather than one joint policy can significantly improve exploration. Our key idea is to guide each member of the population to explore different regions of the environment. To this end, we propose a member-aware exploration objective which explicitly guides each member to maximize deviation from the explored regions of other members, thus forcing them to explore different regions. In addition, we further propose an exploration-enhanced policy constraint to guide each member to learn a joint policy that is both different from other members and promotes exploration, thus increasing the probability of exploring different regions. Under reward-free setting, our method achieves 72% average improvement in the number of explored states compared to classical exploration methods in the multiple-particle environment. Moreover, under sparse-reward setting, we show that the proposed method significantly outperforms the state-of-the-art methods in the multiple-particle environment, the Google Research Football, and StarCraft II micromanagement tasks.
Intention Progression with Temporally Extended Goals
Authors: Yuan Yao; Natasha Alechina; Brian Logan
Venue: IJCAI 2024 (main)

Abstract: The Belief-Desire-Intention (BDI) approach to agent development has formed the basis for much of the research on architectures for autonomous agents. A key advantage of the BDI approach is that agents may pursue multiple intentions in parallel. However, previous approaches to managing possible interactions between concurrently executing intentions are limited to interactions between simple achievement goals (and in some cases maintenance goals). In this paper we present a new approach to intention progression for agents with temporally extended goals which allow mixing reachability and invariant properties, e.g., ``travel to location A while not exceeding a gradient of 5%''. Temporally extended goals may be specified at run-time (top-level goals), and as subgoals in plans. In addition, our approach allows human-authored plans and plans implemented as RL policies to be freely mixed in an agent program, allowing the development of agents with `neuro-symbolic' architectures.
ADMN: Agent-Driven Modular Network for Dynamic Parameter Sharing in Cooperative Multi-Agent Reinforcement Learning
Authors: Yang Yu; Qiyue Yin; Junge Zhang; Pei Xu; Kaiqi Huang
Venue: IJCAI 2024 (main)

Abstract: Parameter sharing is a common strategy in multi-agent reinforcement learning (MARL) to make the training more efficient and scalable. However, applying parameter sharing among agents indiscriminately hinders the emergence of agents diversity and degrades the final cooperative performance. To better balance parameter sharing and agents diversity, we propose a novel Agent-Driven Modular Network (ADMN), where agents share a base network consisting of multiple specialized modules, and each agent has its own routing to connect these modules. In ADMN, modules are shared among agents to improve the training efficiency, while the combination of different modules brings rich diversity. The agent routing at different time steps is learned end-to-end to achieve a dynamic and adaptive balance. Specifically, we also propose an information-theoretical regularization between the routing of agents and their behavior to further guarantee the identifiability of different routing. We evaluated ADMN in challenging StarCraft micromanagement games and Google Research Football games, and results demonstrate the superior performance of ADMN, particularly in larger or heterogeneous cooperative tasks.
Guidance Graph Optimization for Lifelong Multi-Agent Path Finding
Authors: Yulun Zhang; He Jiang; Varun Bhatt; Stefanos Nikolaidis; Jiaoyang Li
Venue: IJCAI 2024 (main)

Abstract: We study how to use guidance to improve the throughput of lifelong Multi-Agent Path Finding (MAPF). Previous studies have demonstrated that, while incorporating guidance, such as highways, can accelerate MAPF algorithms, this often results in a trade-off with solution quality. In addition, how to generate good guidance automatically remains largely unexplored, with current methods falling short of surpassing manually designed ones. In this work, we introduce the guidance graph as a versatile representation of guidance for lifelong MAPF, framing Guidance Graph Optimization as the task of optimizing its edge weights. We present two GGO algorithms to automatically generate guidance for arbitrary lifelong MAPF algorithms and maps. The first method directly optimizes edge weights, while the second method optimizes an update model capable of generating edge weights. Empirically, we show that (1) our guidance graphs improve the throughput of three representative lifelong MAPF algorithms in eight benchmark maps, and (2) our update model can generate guidance graphs for as large as 93 x 91 maps and as many as 3,000 agents. We include the source code at: https://github.com/lunjohnzhang/ggo_public. All optimized guidance graphs are available online at: https://yulunzhang.net/publication/zhang2024ggo.
Towards a Pretrained Model for Restless Bandits via Multi-arm Generalization
Authors: Yunfan Zhao; Nikhil Behari; Edward Hughes; Edwin Zhang; Dheeraj Nagaraj; Karl Tuyls; Aparna Taneja; Milind Tambe
Venue: IJCAI 2024 (main)

Abstract: Restless multi-arm bandits (RMABs) is a class of resource allocation problems with broad application in areas such as healthcare, online advertising, and anti-poaching. We explore several important question such as how to handle arms opting-in and opting-out over time without frequent retraining from scratch, how to deal with continuous state settings with nonlinear reward functions, which appear naturally in practical contexts. We address these questions by developing a pre-trained model (PreFeRMAB) based on a novel combination of three key ideas: (i) to enable fast generalization, we use train agents to learn from each other's experience; (ii) to accommodate streaming RMABs, we derive a new update rule for a crucial $\lambda$-network; (iii) to handle more complex continuous state settings, we design the algorithm to automatically define an abstract state based on raw observation and reward data. PreFeRMAB allows general zero-shot ability on previously unseen RMABs, and can be fine-tuned on specific instances in a more sample-efficient way than retraining from scratch. We theoretically prove the benefits of multi-arm generalization and empirically demonstrate the advantages of our approach on several challenging, real-world inspired problems.
Pluggable Watermarking of Deepfake Models for Deepfake Detection
Authors: Han Bao; Xuhong Zhang; Qinying Wang; Kangming Liang; Zonghui Wang; Shouling Ji; Wenzhi Chen
Venue: IJCAI 2024 (main)

Abstract: Deepfake model misuse poses major security concerns. Existing passive and active Deepfake detection methods both suffer from a lack of generalizability and robustness. In this study, we propose a pluggable and efficient active model watermarking framework for Deepfake detection. This approach facilitates the embedding of identification watermarks across a variety of Deepfake generation models, enabling easy extraction by authorities for detection purposes. Specifically, our method leverages the universal convolutional structure in generative model decoders. It employs convolutional kernel sparsification for adaptive watermark embedding positioning and introduces convolutional kernel normalization to seamlessly integrate watermark parameters with those of the generative model. For watermark extraction, we jointly train a watermark extractor based on a Deepfake detection model and use BCH encoding to identify watermark images effectively. Finally, we apply our approach to eight major types of Deepfake generation models. Experiments show our method successfully detects Deepfakes with an average accuracy exceeding 94% even in heavy lossy channels. This approach operates independently of the generation model's training without affecting the original model's performance. Furthermore, our model requires training a very limited number of parameters, and it is resilient against three major adaptive attacks. The source code can be found at https://github.com/GuaiZao/Pluggable-Watermarking
Discriminative Feature Decoupling Enhancement for Speech Forgery Detection
Authors: Yijun Bei; Xing Zhou; Erteng Liu; Yang Gao; Sen Lin; Kewei Gao; Zunlei Feng
Venue: IJCAI 2024 (main)

Abstract: The emergence of AIGC has brought attention to the issue of generating realistic deceptive content. While AIGC has the potential to revolutionize content creation, it also facilitates criminal activities. Specifically, the manipulation of speech has been exploited in tele-fraud and financial fraud schemes, posing a significant threat to societal security. Current deep learning-based methods for detecting forged speech extract mixed features from the original speech, which often contain redundant information. Moreover, these methods fail to consider the distinct characteristics of human voice-specific features and the diversity of background environmental sounds. This paper introduces a framework called Discriminative fEature dEcoupling enhanceMent (DEEM) for detecting speech forgery. Initially, the framework decouples the original speech into human voice features and background sound features. Subsequently, DEEM enhances voice-specific features through temporal dimension aggregation and improves continuity-related features in the background sound map via spectral-dimension aggregation. By employing the decoupling enhancement features, extensive experiments demonstrate that DEEM achieves an accuracy improvement of over 5% on FoR dataset compared to the state-of-the-art methods.
BadFusion: 2D-Oriented Backdoor Attacks against 3D Object Detection
Authors: Saket S. Chaturvedi; Lan Zhang; Wenbin Zhang; Pan He; Xiaoyong Yuan
Venue: IJCAI 2024 (main)

Abstract: 3D object detection plays an important role in autonomous driving; however, its vulnerability to backdoor attacks has become evident. By injecting “triggers” to poison the training dataset, backdoor attacks manipulate the detector's prediction for inputs containing these triggers. Existing backdoor attacks against 3D object detection primarily poison 3D LiDAR signals, where large-sized 3D triggers are injected to ensure their visibility within the sparse 3D space, rendering them easy to detect and impractical in real-world scenarios. In this paper, we delve into the robustness of 3D object detection, exploring a new backdoor attack surface through 2D cameras. Given the prevalent adoption of camera and LiDAR signal fusion for high-fidelity 3D perception, we investigate the latent potential of camera signals to disrupt the process. Although the dense nature of camera signals enables the use of nearly imperceptible small-sized triggers to mislead 2D object detection, realizing 2D-oriented backdoor attacks against 3D object detection is non-trivial. The primary challenge emerges from the fusion process that transforms camera signals into a 3D space, compromising the association with the 2D trigger to the target output. To tackle this issue, we propose an innovative 2D-oriented backdoor attack against LiDAR-camera fusion methods for 3D object detection, named BadFusion, for preserving trigger effectiveness throughout the entire fusion process. The evaluation demonstrates the effectiveness of BadFusion, achieving a significantly higher attack success rate compared to existing 2D-oriented attacks.
Machine Unlearning via Null Space Calibration
Authors: Huiqiang Chen; Tianqing Zhu; Xin Yu; Wanlei Zhou
Venue: IJCAI 2024 (main)

Abstract: Machine unlearning aims to enable models to forget specific data instances when receiving deletion requests. Current research centers on efficient unlearning to erase the influence of data from the model and neglects the subsequent impacts on the remaining data. Consequently, existing unlearning algorithms degrade the model's performance after unlearning, known as over-unlearning. This paper addresses this critical yet under-explored issue by introducing machine Unlearning via Null Space Calibration (UNSC), which can accurately unlearn target samples without over-unlearning. On the contrary, by calibrating the decision space during unlearning, UNSC can significantly improve the model's performance on the remaining samples. In particular, our approach hinges on confining the unlearning process to a specified null space tailored to the remaining samples, which is augmented by strategically pseudo-labeling the unlearning samples. Comparison against several established baselines affirms the superiority of our approach.
Are Logistic Models Really Interpretable?
Authors: Danial Dervovic; Freddy Lecue; Nicolas Marchesotti; Daniele Magazzeni
Venue: IJCAI 2024 (main)

Abstract: The demand for open and trustworthy AI models points towards widespread publishing of model weights. Consumers of these model weights must be able to act accordingly with the information provided. That said, one of the simplest AI classification models, Logistic Regression (LR), has an unwieldy interpretation of its model weights, with greater difficulties when extending LR to generalised additive models. In this work, we show via a User Study that skilled participants are unable to reliably reproduce the action of small LR models given the trained parameters. As an antidote to this, we define Linearised Additive Models (LAMs), an optimal piecewise linear approximation that augments any trained additive model equipped with a sigmoid link function, requiring no retraining. We argue that LAMs are more interpretable than logistic models -- survey participants are shown to solve model reasoning tasks with LAMs much more accurately than with LR given the same information. Furthermore, we show that LAMs do not suffer from large performance penalties in terms of ROC-AUC and calibration with respect to their logistic counterparts on a broad suite of public financial modelling data.