Interacting with ridesharing systems is a complex spatiotemporal task. Traditional approaches rely on the full disclosure of a client's trip information to perform ride matching. However during poor service conditions of low supply or high demand, this requirement may mean that a client cannot find any ride matching their intentions. To address this within real-world road networks, we extend our map-based opportunistic client user interface concept, i.e., launch pads, from a discrete to a continuous space-time representation of vehicle accessibility to provide a client with a more realistic choice set. To examine this extension under different conditions, we conduct two computational experiments. First, we extend our previous investigation into the effects of varying vehicle flexibility and population size on launch pads and a client's probability of pick-up, describing the increased opportunity. Second, observing launch pads within a real-world road network, we analyze aspects of choice and propose necessary architecture improvements. The communication of ride share potential using launch pads provides a client with a simple yet flexible means of interfacing with on-demand transportation.

Existing ride sharing systems for commuting in urban environments are rigid. They rely on the communication of discrete, spatio-temporal constraints from both vehicle and client to perform ride-matching. From a client user perspective these approaches are problematic, leading to location-privacy issues and the use of additional communication channels for ad-hoc negotiation which cannot be immediately quantified. To account for these aspects, we develop a dynamic, intuitive interface technique called launch pads and a centralized system architecture, which together simplify the ride-matching process whilst preserving location-privacy. The results of two experiments reveal the latent potential existing within ride sharing systems if vehicle flexibility is quantified and incorporated into a representation of accessibility. The communication via launch pads provides a client with means to fully exploit this potential.

This paper reports on our experiences with using the emerging Web service technologies and tools to create a demonstration information broker system as part of our research into information management in a distributed environment. To provide a realistic context, we chose to study the use of information in the healthcare domain, and this context sets some challenging parameters and constraints for our research and for the demonstration system. In this paper, we both report on the extent to which existing Web service technologies have proved to be mature enough to meet these requirements, and also assess their current limitations.

We address the problem of large-scale data integration, where the data sources are unknown at design time, are from autonomous organisations, and may evolve. Experiments are described involving a demonstrator system in the field of health services data integration within the UK. Current Web services technology has been used extensively and largely successfully in these distributed prototype systems. The work shows that Web services provide a good infrastructure layer, but integration demands a higher level "broker" architectural layer; the paper identifies eight specific requirements for such an architecture that have emerged from the experiments, derived from an analysis of shortcomings which are collectively due to the static nature of the initial prototype. The way in which these are being met in the current version in order to achieve a more dynamic integration is described.