The number of mobile phone subscriptions worldwide is increasing on a daily basis and so is the number of services offered to customers and applications running on mobile phones. Mobile phones have a number of valuable features, which have given them the potential to become the one and only operational large-scale wireless sensor network. Their pervasive communication, built-in and expandable sensing functionality, powerful processing capability and memory capacity, reasonable small size, light weight, and public availability as well as ubiquitous network infrastructures have made them suitable sensing, communication, processing, and data muling devices. Mobile phones are now all about data, services, and applications as voice usage decreases. An interesting observation here is the willingness and interest of mobile consumers to enhance their experience and performance of the applications at hand on a voluntary basis.

This special issue solicits original contributions, addressing trends, potential, requirements, and challenges of use of mobile phones on a voluntary and participatory basis for monitoring, maintenance, and control applications. Papers describing novel solutions and practical approaches or engineering contributions, which are extensively tested either in simulation environments and/or real-world experimental settings are specially welcome.

Topics of interest include, but not limited to:
• Participatory sensing, crowdsourcing, and opportunistic sensing paradigms and applications
• Novel architectures to support participatory sensing applications
• Large scale mobile and sensing data mining, learning, and reasoning
• Mobile cloud computing
• Experiment and campaign design
• Availability and research prototypes of miniature sensors and their integration into cellular phones
• Integration of on-phone and off-phone sensing
• Incentive paradigms for mobile sensing applications
• Energy efficient and computationally inexpensive privacy preservation and security mechanisms
• Data validation techniques to deal with erroneous data (intentionally and unintentionally)
• Data visualization techniques
• New business models for mobile sensing data and applications
• Software platforms for remote sensing using smartphones
• Effect of mobility models on opportunistic collaboration