The theme of the 39th COMPSAC is "Mobile and Cloud Systems - Challenges and Applications." With the rapidly growing trend in making computations and data both mobile and cloud-based, such systems are being designed and deployed worldwide. However, there still exists several challenges when they are applied to different domains or across domains. For example, the increasing convergence of applications in handheld devices have led to the mobile gadgets being a part of everyone's life. The hardware and software design in mobile systems with cloud-based delegation of data/computation has introduced several new challenges such as high power consumption, prolonged delays, security issues, big data, software engineering, human-machine interface, and hierarchical or cross-platform integration issues. COMPSAC 2015 will provide a platform for in-depth discussion of such challenges in emerging application domains such as Smart and connected health, wearable computing, internet-of-things, cyber-physical systems, and smart planet. COMPSAC 2015 will be organized as a tightly integrated union of several symposia, each of which will be focusing on a particular technical segment. Further, COMPSAC 2015 will also include student research competition, doctoral symposium, and fast abstract, in addition to special sessions, panels, and keynotes to facilitate discourse on and deepen the understanding of the challenges by furthering the fundamental contributions needed for advances in computing systems.