arXiv subjects

Satoshi Furutani

Publications and source records attributed to Satoshi Furutani.

3 recordsLinked to original sources

arXiv2026

The Impact of Micro-level User Interventions on Macro-level Misinformation Spread

User interventions such as nudges, prebunking, and contextualization have been widely studied as countermeasures against misinformation, and shown to suppress individual users' sharing behavior. However, it remains unclear whether and to what extent such individual-level effects translate into reductions in collective misinformation prevalence. In this study, we incorporate user interventions as reductions in users' susceptibility within an empirically calibrated network-based misinformation diffusion model. We then systematically evaluate how intervention strength, scale, timing, target selection, and combinations of interventions affect overall misinformation prevalence through numerical simulations. The simulation results reveal that current user-level interventions may not necessarily produce sufficient collective effects. Specifically, each intervention alone only modestly suppresses misinformation prevalence, and even when design adjustments such as expanding intervention scale, implementing interventions earlier, or strategically selecting target users are introduced, the resulting gains in suppression remain limited. Although combining multiple interventions improves the suppression effect compared to using each intervention alone, achieving substantial reductions in misinformation prevalence remains difficult within realistically attainable intervention levels. This study quantitatively clarifies the gap between micro-level user interventions and macro-level misinformation spread, and demonstrates the limitations of evaluating misinformation countermeasures based solely on individual-level effectiveness.

cs.SI↗

arXiv2025

Network Prebunking Problem: Optimizing Prebunking Targets to Suppress the Spread of Misinformation in Social Networks

As a countermeasure against misinformation that undermines the healthy use of social media, a preventive intervention known as \textit{prebunking} has recently attracted attention in the field of psychology. Prebunking aims to strengthen individuals' cognitive resistance to misinformation by presenting weakened doses of misinformation or by teaching common manipulation techniques before they encounter actual misinformation. Despite the growing body of evidence supporting its effectiveness in reducing susceptibility to misinformation at the individual level, an important open question remains: how best to identify the optimal targets for prebunking interventions to mitigate the spread of misinformation in a social network. To address this issue, we formulate a combinatorial optimization problem, called the \textit{network prebunking problem}, which aims to select optimal prebunking targets that minimizes the spread of misinformation in a social network under limited intervention budgets. We show that the problem is NP-hard and that its objective function is monotone and submodular, which provides a theoretical foundation for approximation guarantees of greedy algorithms. However, since the greedy algorithm is computationally expensive and does not scale to large networks, we propose an efficient approximation algorithm, MIA-NPP, based on the Maximum Influence Arborescence (MIA) approach, which restricts influence propagation around each node to a local directed tree rooted at that node. Through numerical experiments using real-world social network datasets, we demonstrate that MIA-NPP effectively suppresses the spread of misinformation under both fully observed and uncertain model parameter settings.

cs.SI↗

arXiv2022

Interpreting Graph-based Sybil Detection Methods as Low-Pass Filtering

Online social networks (OSNs) are threatened by Sybil attacks, which create fake accounts (also called Sybils) on OSNs and use them for various malicious activities. Therefore, Sybil detection is a fundamental task for OSN security. Most existing Sybil detection methods are based on the graph structure of OSNs, and various methods have been proposed recently. However, although almost all methods have been compared experimentally in terms of detection performance and noise robustness, theoretical understanding of them is still lacking. In this study, we show that existing graph-based Sybil detection methods can be interpreted in a unified framework of low-pass filtering. This framework enables us to theoretically compare and analyze each method from two perspectives: filter kernel properties and the spectrum of shift matrices. Our analysis reveals that the detection performance of each method depends on how well low-pass filtering can extract low frequency components and remove noisy high frequency components. Furthermore, on the basis of the analysis, we propose a novel Sybil detection method called SybilHeat. Numerical experiments on synthetic graphs and real social networks demonstrate that SybilHeat performs consistently well on graphs with various structural properties. This study lays a theoretical foundation for graph-based Sybil detection and leads to a better understanding of Sybil detection methods.

cs.CR↗