Mobile crowdsourcing [Editor´s note]

Crowdsourcing is the combination of two concepts, ???crowd??? and ???outsourcing,??? coined by Jeff Howe in 2006, and defined as ???the act of taking a job traditionally performed by a designated agent (usually an employee) and outsourcing it to an undefined, generally large group of people in the form of an open call.??? In modern society, the rapid advances of mobile and communication technologies significantly enhance the applications and popularization of crowdsourcing. Most mobile devices today are equipped with powerful processors, various sensors, large memories, and fast wireless communication modules, etc. Due to the integration of these sophisticated components, mobile devices have become one kind of the important tools to sense, communicate, and compute data. For instance, smartphones can be used to collect video/image data (with cameras), acoustic data (with microphone), location information (with GPS), and other useful contextual information (with a gyroscope and accelerometers), etc. They can also transmit data via cellular networks, WiFi, and bluetooth, etc. According to the forecasts from Canalys, worldwide mobile device shipments, including notebooks, tablets, smart phones, etc., will exceed 2.6 billion units by 2016. Those powerful mobile devices not only make the crowdsourcing tasks easier to be taken by the crowd, but also enrich the diversity of crowdsourcing tasks.