“…Devices enabled with pervasive computing technologies, such as, smart cards [1], [2], wearable devices [3], Radio-Frequency (RF) communication devices (RFCD) (e.g., mobile phones [4], [5], [6], Bluetooth [7], [8], [9], [10], Wireless Fidelity (WiFi) [11], [12], [13], RadioFrequency ID (RFID), and Global Positioning System (GPS) [14], [15], [16]), Optical-Wireless communication (OWC) (e.g., infrared or IR devices) [17], video surveillance [18], [19], [20], in conjunction with social media [21], [22], [23] and different event websites are part and parcel of our daily lives. Recent studies report that the above mentioned ubiquitous technologies can also be employed as sensors to collect data on human activities from the urban space and are uploaded to distributed / centralized databases.…”