Mobile devices are increasingly being relied on for services that go beyond simple connectivity and require more complex processing. Fortunately, a mobile device encounters, possibly intermittently, many entities capable of lending it computational resources. At one extreme is the traditional cloud-computing context where a mobile device is connected to remote cloud resources maintained by a service provider with which it has an established relationship. In this paper we consider the other extreme, where a mobile device's contacts are only with other mobile devices, where both the computation initiator and the remote computational resources are mobile, and where intermittent connectivity among these entities is the norm. We present the design and implementation of a system, Serendipity, that enables a mobile computation initiator to use remote computational resources available in other mobile systems in its environment to speedup computing and conserve energy. We propose a simple but powerful job structure that is suitable for such a system. Serendipity relies on the collaboration among mobile devices for task allocation and task progress monitoring functions. We develop algorithms that are designed to disseminate tasks among mobile devices by accounting for the specific properties of the available connectivity. We also undertake an extensive evaluation of our system, including experience with a prototype, that demonstrates Serendipity's performance.

This paper discusses the evolution towards the first integrated radio-frequency identification (RFID)-enabled wireless sensor network infrastructure using ultra-high frequency/radio frequency (UHF/RF) RFID-enabled sensor nodes and inkjet-printed electronics technologies on flexible and paper substrates for the first time ever. The first sections highlight the unique capabilities of inkjet printed electronics as well as the benefits of using paper as the ultra-low-cost, conformal and environmentally friendly substrate for the mass-scale ubiquitous implementation of the first RFID-enabled wireless sensing applications. Various inkjet-printed antenna configurations are presented for enhanced-range compact RFID-enabled sensing platforms in “rugged” environments up to 7 GHz, followed by the discussion of their 2-D integration with integrated circuit (IC) and sensors on paper. This integration is extended to a power-scavenging “smart-shoe” batteryless integrated RFID module on paper that could be used for autonomous wearable sensing applications with enhanced range. The paper concludes discussing the details for establishing for the first time an asynchronous wireless link between the aforementioned RFID-tags and a widely used commercial wireless sensor network (WSN) mote using a simplified protocol; a paramount step that could potentially create ubiquitous ultra-low-cost sensor networks and large-scale RFID implementations eliminating the need of expensive RFID reader infrastructure and linking RFIDs to the mature level of WSNs.