The Marlin project is exploring the design and implementation of a middleware layer for permitting mobile applications and their users to interact effectively with web-based services.  The vision of applications that dynamically configure themselves out of various web services is a compelling one, but raises some difficult issues in a mobile computing world where devices often operate while disconnected from the Internet and where personalized services are required to adapt to the limited resources on mobile devices.  With the rapid growth in the use of mobile devices, it is vital to understand how best to support such devices in a computing world built around web services.

Note: Due to other commitments by lab members, particularly Doug Terry's substantial involvement with a product group, this project currently is not a major focus of activity in the lab.  For the time being, this research is proceeding as a low-priority, part-time effort.

• Doug Terry

Research questions in the area of mobility and web services include the following:

        What are the best mechanisms for replicating web services (and their data) onto mobile devices?  Should the replication process propagate operations or data objects?  Whats the appropriate level of consistency to maintain?  How should conflicting updates to web services be detected and resolved?

        Can and should the same mechanism be used for (a) replicating web services onto mobile devices to support disconnected operation and (b) replicating web services within a network for high availability?

        Can secure web services be replicated or cached on insecure mobile devices?

        For mobile devices that cannot run a full web service or all of its data, is it useful to cache a partial web service?  How is this done?

        How do mobile applications recover from failed web services or from the loss of connectivity to a service that is being accessed? 

        For context-driven web services, what is the best way to manage a users relevant context (location, schedule, contacts, priorities, etc.) and make it available to services without unduly violating the users privacy?  Should My Context be a new type of web service?

        Is the Pocket PC a reasonable platform for accessing and caching web services?  Can Pocket PCs also host web services?

        For handheld mobile devices with wireless connectivity, such as cell phones, is WAP (Wireless Application Protocol) a reasonable means for accessing web services?

        In a peer-to-peer network of mobile devices, how do the devices discover what web services are available to them through others?  How does a mobile device balance its desire to provide web services to others with its need to manage its scarce resources?

        What are useful Quality of Service (QoS) metrics for web services?  Which of these are needed by mobile devices?  How can they be enforced?

• Caching XML Web Services for Mobility. ACM Queue, Vol. 1, No. 3, May 2003.