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  • Iterative expectation maxim...
    Ma, Lijia; Tay, Wee Peng; Xiao, Gaoxi

    Information sciences, October 2019, 2019-10-00, Volume: 501
    Journal Article

    •This paper is to find the truth Z of events in social sensing with information flows.•A truth discovery model is presented which considers the individuals’ reliability R.•The model also considers the dependency D between individuals’ observations.•An iterative expectation maximization is presented to infer both Z, R and D.•Extensive experiments demonstrate the effectiveness of the presented algorithm. Social sensing relies on a large number of observations reported by different, possibly unreliable, agents to determine if an event has occurred or not. In this paper, we consider the truth discovery problem in social sensing, in which an agent may receive another agent’s observation (known as an information flow), and may change its observation to match the observation it receives. If an agent’s observation is influenced by another agent, we say that the former is a dependent agent. We propose an Iterative Expectation Maximization algorithm for Truth Discovery (IEMTD) in social sensing with dependent agents. Compared with other popular truth discovery approaches, which assume either the agents’ observations are independent, or their dependency is known a priori, IEMTD allows to infer each agent’s reliability, the observations’ dependency and the events’ truth jointly. Simulation results on synthetic data and three real world data sets demonstrate that in almost all our experiments, IEMTD achieves a higher truth discovery accuracy than the existing algorithms when dependencies exist between agents’ observations.