<p>In recent years, the mobile gaming industry has made rapid progress. Developers are now producing numerous mobile games with increasingly immersive graphics. However, these resource-hungry applications inevitably keep pushing well beyond the hardware limits of mobile devices. The limitations causes two main challenging issues for mobile game players. First, limited computational capabilities of smart devices are preventing rich multimedia applications from running smoothly. Second, the minuscule touchscreens impede the players from smoothly interacting with devices as they can do with PCs. This thesis aims to address the two issues. Specifically, we implement two systems, one for the application accelerations via offloading and the other for alternative interaction approach for mobile gaming. We identify and describe the the challenging issues when developing the systems and describe our corresponding solutions. Regarding the first system, it is well recognized the performance of GPUs on mobile devices is the bottleneck of rich multimedia mobile applications such as 3D games and virtual reality. Previous attempts to tackle the issue mainly mirgate GPU computation to servers residing in remote datacenters. However, the costly network delay is especially undesirable for highly-interactive multimedia applications since a crisp response time is critical for user experience. In this thesis, we propose GBooster, a system that accelerates GPU-intensive mobile applications by transparently offloading GPU tasks onto neighboring multimedia devices such as SmartTV and Gaming Consoles. Specifically, GBooster intercepts and redirects system graphics calls by utilizing the Dynamic Linker Hooking technique, which requires no modification of the apps and mobile systems. Besides, GBooster intelligently switches between the low-power Bluetooth and the high-bandwidth WiFi interface to reduce energy consumption of network transmissions. We implemented the GBooster on the Android system and evauluate its performance. The results demonstrate that GBooster can boost applications' frame rates by up to {85\%}. In terms of power consumption, GBooster can achieve {70\%} energy saving compared with local execution. Second, we investigate the potential of built-in mobile device sensors to provide an alternative interaction approach for mobile gaming. We propose UbiTouch, a novel system that extends smartphones with virtual touchpads on desktops using built-in smartphone sensors. It senses a user's finger movement with a proximity and ambient light sensor whose raw sensory data from underlying hardware are strongly dependent on the finger's locations. UbiTouch maps the raw data into the finger's positions by utilizing Curvilinear Component Analysis and improve tracking accuracy via a particle filter. We have evaluate our system in three scenarios with different lighting conditions by five users. The results show that UbiTouch achieves centimetre-level localization accuracy and poses no significant impact on the battery life. We envisage that UbiTouch could support applications such as text-writing and drawing.</p>
From Data Acquisition to Data Fusion: A Comprehensive Review and a Roadmap for the Identification of Activities of Daily Living Using Mobile Devices