Big sensor data applications in urban environments

The emergence of new technologies such as Internet/Web/Network-of-Things and large scale wireless sensor systems enables the collection of data from an increasing volume and variety of networked sensors for analysis. In this review article, we summarize the latest developments of big sensor data systems (a term to conceptualize the application of the big data model towards networked sensor systems) in various representative studies for urban environments, including for air pollution monitoring, assistive living, disaster management systems, and intelligent transportation. An important focus is the inclusion of how value is extracted from the big data system. We also discuss some recent techniques for big data acquisition, cleaning, aggregation, modeling, and interpretation in large scale sensor-based systems. We conclude the paper with a discussion on future perspectives and challenges of sensor-based data systems in the big data era.