A framework for universal service access using device ensemble.pdf

1A Framework for Universal Service Access using Device Ensemble Z. Morley Mao, Randy H. Katz {zmao, randy}@ Computer Science Division, EECS Department, University of California at Berkeley, CA, USA Abstract— As more wireless devices become available and new applica- tions emerge for these diverse gadgets, there is an increasing need to in- telligently adapt existing services (e.g., Web browsing, video streaming) to them. Adaptation is needed due to heterogeneous and vastly differing ca- pabilities in hardware, software, and network connectivity. We argue that existing services should remain unmodified and a automatically created, adaptive, distributed service proxy architecture with properties of fault- tolerance, composability is necessary for creating truly mobile services us- ing a collection of devices. These devices form a device ensemble or a virtual device. We demonstrate feasibility of such an architecture based on our previous work in wide-area service composition [1]. I. INTRODUCTION Today, there exists a spectrum of devices with different net- working, hardware, and software capability. At one end of the spectrum are small mobile devices with relatively poor net- work connectivity, low computational power, limited memory and battery supply. Examples are various PDAs (e.g., Palm and iPAQ Pocket PC), pagers, smartdust motes [2], and cellular phones. At the other end of the spectrum exist more powerful devices such as desktop machines, laptop computers, and public kiosks. There is an inevitable mismatch between existing ser- vices and devices in the former group. To access a service using such a device, the current model of service adaptation neither scales nor enables rapid service deployment due to the model of vertical integration. WAP [3]-enabled cell phones, for example, requires Web pages to be encoded in WML before they can be displayed for small devices. Reencoding all existing Web pages using WML is an impossible task. Furthermore, such a solu- tion