Motivated by real-world applications, we study the problem of decentralized online learning with dynamic feedback delays in the presence of malicious data generators under different threat models. In this problem, multiple agents collaborate to classify the features of streaming data samples generated online and receive dynamically delayed feedback on the ground-truth labels. While some data generators are benign, others—due to internal motives or external factors such as cyberattacks—may maliciously manipulate data features to compromise the classification performance. In this work, we first investigate the targeted attacks by malicious data generators, i.e., feature manipulation with aims to gain preferred classification outcomes from the agents. In response, we propose two robust algorithms,RDOC-TOandRDOC-TC, countering ordinary and clairvoyant adversaries that can access certain outdated and the latest classification models of the agents, respectively. Subsequently, we address the untargeted attacks by malicious data generators, which aim to disrupt the classification outcomes without targeting any particular class, by proposing another algorithm,RDOC-U. Our theoretical analysis establishes that all three proposed algorithms achieve sublinear regret bounds. The evaluations conducted in the application of network traffic classification with two real-world datasets demonstrate the competitiveness of the proposed algorithms compared to advanced baselines.

Ride-sharing represents a sustainable transportation paradigm that is beneficial to human, society, and environment. Common ride-sharing pricing approaches determine prices for riders through optimizing one or more figures of merit, e.g., the profit or revenue. However, they overlook an important issue—fairness—which, when perceived by the riders, can critically affect their degree of satisfaction. In this work, we take the initiative to consider an intuitive and appropriate notion of individual fairness called fairness-in-hindsight for riders in ride-sharing pricing. We study the problem of online fair pricing of shared rides (which allow multiple riders to share one ride) with an aim to maximize the profit of the ride-sharing operator/platform. We design an online fair ride-sharing pricing algorithm called OnFairRP, which comprises phases oflearning, transition, and exploitation. We prove that OnFairRP has a sub-linear regret bound and can guarantee the fairness between riders. Our extensive performance evaluations using real-world data traces of ride-sharing demonstrate the advantages of OnFairRP over benchmarking schemes including commonly used methods with or without fairness guarantee.

We conduct an incentivized laboratory experiment to study people's perception of generative artificial intelligence (GenAI) alignment in the context of economic decision-making. Using a panel of economic problems spanning the domains of risk, time preference, social preference, and strategic interactions, we ask human subjects to make choices for themselves and to predict the choices made by GenAI on behalf of a human user. These problems confront agents with trade-offs (e.g., higher payoff vs. earlier payoff, efficiency vs. equity, riskier but potentially higher rewards vs. safer but lower rewards) and the optimal choices depend on the agent's preferences. We find that people overestimate the degree to which GenAI choices are aligned with human preferences in general (anthropomorphic projection), and with their personal references in particular (self projection). On average, human subjects' predictions about GenAI's choices in every decision environment are much closer to the average human-subject choice than to the average GenAI choice. At the individual level, human subjects' predictions about GenAI's choices in a given environment are highly correlated with their own choices in the same environment.

Motivated by the real-world application of traffic classification at the network edge, we study the problem of robust decentralized online learning against malicious data generators that can manipulate their data features with an aim to gain preferred classification outcomes. Multiple agents cooperatively learn classification models to make online decisions. They periodically exchange their models, e.g., traffic classification models, between neighbors in a decentralized network and update local model parameters on the fly based on the models they have access to and feedback on the observed local data samples that are dynamically delayed. In this work, we propose two decentralized online learning algorithms, RDOC-O and RDOC-C, respectively against ordinary malicious and clairvoyant malicious data generators. Our theoretical performance analysis shows that the two algorithms have provable sub-linear individual regret bounds under mild conditions. To validate our analysis, extensive performance evaluations are conducted in the application of network traffic classification using two real-world data traces. Our results show that the two proposed algorithms compare favorably with an optimal offline classification model in the presence of malicious data generators, and they can achieve a steady-state F1score of around 0.85, which validates their effectiveness and makes them appealing in practice.