Mobile computing networks

Citation

Rudall, B.H. (2000), "Mobile computing networks", Kybernetes, Vol. 29 No. 1. https://doi.org/10.1108/k.2000.06729aaa.008

Mobile computing networks

Mobile computing networks

Keywords: Automation, Cybernetics, Research

In the UK, the Engineering and Physical Sciences Research Council (EPSRC) has encouraged research into the support for mobile computing networks. One recently completed project funded by EPSRC has developed a new way of maintaining the quality of complex computer networks. This has been accomplished by Lancaster University, which developed a novel distribution systems architecture which can adapt automatically to meet changing needs of mobile computing environments. In a recent report to the EPSRC the innovations of Lancaster researchers in producing innovations in their approach was highlighted. Their new distributed systems approach focused on "reactive services". These, we are told, can monitor their environment and alter their behaviour on detecting significant changes, such as a drop in the quality of communications links. Professor Gordon Blair of Lancaster's Distributed Multimedia Research Group (DMRG) is quoted as saying that:

Future computer environments will include mobile computers, with many different levels of connectivity, such as being disconnected or having weak low-speed wireless or fully-connected high speed links.

The report says that:

A recently completed EPSRC-funded project led by Professor Blair and Dr Davies demonstrated that the reactive-service concept can effectively support mobile computing services by exploiting the differing connectivity levels to maintain specified quality of service (QoS) levels. A key outcome of the project was the reactive adaptive proxy placement (RAPP) architecture (see Figure 1), which operates within the internationally recognised common object request broker architecture (CORBA). RAPP supports reactive distributed services using objects that act as proxies on behalf of mobile devices. Proxy objects separate wireless and wired environments, and mediate between different link types.

Figure 1The RAPP architecture (Courtesy of EPSRC)

Professor Blair also notes that:

Other architectures employing proxies generally do so in a rather static way. RAPP manages proxies dynamically on the fly, say to install an object into a data stream in response to a decrease in QoS.

RAPP, the report says, selects the right proxy to handle a QoS change identified by a monitoring function, say to deal with a video protocol. A "proxy factory" creates objects of the specified type at the specified location, and a "proxy trader" locates appropriate factories.

In addition to RAPP, Professor Blair's team has invented a new "tuple space" paradigm for mobile transactions. It works in this way:

A tuple is an ordered set of values separated by commas. In this case, they can represent QoS requirements, such as transmission and error rates, battery life and device location. This builds on "generative communication" ideas originated at Yale University (USA). The tuple space "uncouples" sender and receiver in terms of time and space: they do not need to be aware of each other at the same time and do not need to know each others' identities.

Users of such systems will be interested to know that RAPP has been implemented on the OMNIBROKER CORBA platform on SUN/OS and Linux systems. The university researchers have also created a tuple-space platform for Linux, Windows NT and Solaris systems. RAPP and the tuple-space paradigm have been successfully integrated following extensive testing.

The ESRC report also informs us that this approach builds on the expertise gained at Lancaster University by its study on mobile computing for utilities industries. Further development in collaboration with other groups is envisaged with the assistance of other EPSRC grants such as the Adapt and Open-ORB projects.

The report is published in Impact, Issue 23, 1999. Contact with the Lancaster DMRG researchers can be through the Weblink: www.comp.lancs.ac.uk/computing/research/mpg/most/

B.H. Rudall Norbert Wiener Institute and University of Wales, UK