The tremendously rapid popularization of smart phones has significantly impacted our daily lives. Smartphones are used not only for voice communication but also for various purposes such as information search (e.g., Web, Location-Based Services (LBS), etc.), E-commerce (e.g., on-line shopping, trading, etc.), and establishing social relationships (i.e., Social Networking Services (SNSs)). Meanwhile, in the last decade, various new technical advances such as Internet of Things (IoT), machine-to-machine (M2M), Intelligent Transport Systems (ITS), cloud computing, and crowdsourcing have become a big trend and have had significant impacts on both academic and social aspects.