Background - Smartphone-Based Human Activity Recognition - page 15

Fig. 2.2 Example of a commercial smartphone (SGSII) and some of its features

Table 2.2 Common features of current smartphone models in the market
Hardware Sensors Communications Services

CPU Camera Wi-Fi SMS

Battery Accelerometer GPRS MMS

Internal memory Gyroscope EDGE Email

Touchscreen Compass Bluetooth Internet

SD card Proximity USB Third-party apps

SIM card GPS 2G, 3G, 4G Radio

Speakers Barometer NFC Gaming

Light sensor
Microphone

examples of their available features. Figure 2.2 shows an smartphone and lists some
of its features.
Moreover, Table 2.2 lists a set of features available in current smartphone models.
Particular importance should be given to the substantial number of sensors in these
devices, nine in this case. They have been originally included to enhance human-
computer interaction but soon it has been observed that they can bring a broad range
of measuring possibilities for several applications (Lane et al. 2010 ). Nowadays,
they are playing an important role in the exploration of novel information retrieval