This book constitutes the thoroughly refereed post-conference proceedings of the Fourth International Conference on Mobile Computing, Applications, and Services (MobiCASE 2012) held in Seattle, Washington, USA, in October 2012. The 18 revised full papers presented together with 9 revised poster papers were carefully reviewed and selected from 51 submissions. The conference papers are organized in five topical sections, covering mobile application development, multi-dimensional interactions, system support and architecture, mobile applications, and mobile services.

Kochia, a sleepy community on the shores of Lake Victoria in Western Kenya, is caught in the turmoil among traditional ways of life, excitement brought about by development projects and the throes of relentless globalization. Cellphones are spreading HIV and funerals are killing people. Cows are drowning in enormous holes dug by white people. Girls are dropping out of school and children are being rented to orphanages. Crusades and miracle services are blurring the lines between religion and crime. Along with the rapidly declining fish population in the lake, the time to 'teach people how to fish' has passed. It is time for direct and decisive action. Obongo, Okello, Sister Phoebe and friends unravel the complexities of community challenges and design practical solutions to address them. From cardboard coffins to toothbrush currencies and professional praising services, the solutions are simple, frugal and ingenious. The Kochia Chronicles take readers headlong into the lives and adventures of people in this quintessential African village as they usher in an era of design, innovation and entrepreneurship. The Kochia Chronicles owe their genesis to the author's experiences in conducting research and advancing technology-based social ventures in East Africa over the past decade. They draw heavily from the vast literature on development studies and the work of several innovators and entrepreneurs. The stories weave a compelling web of concepts, approaches, facts, statistics, norms, musings, emotions...and full-page illustrations to help readers empathize with the people, their context, and their choices. The Kochia Chronicles are fictitious narratives that bring to life the paradoxical simplicity and complexity of development challenges with the objective of informing and inspiring innovation that leads to the self-determined improvement of lives and livelihoods.