The application of Direct Combination to Mobile and Ubiquitous Human Computer Interaction

Direct Combination is a recently introduced user interaction principle. The principle (previously applied in the desktop computing context) and its associated techniques have the capacity in certain circumstances to reduce significantly the degree of search required to operate user interfaces. In this paper we argue that the Direct Combination principle (DC) applies particularly aptly to mobile computing devices, given appropriate interaction techniques, examples of which are presented here. We argue that the reduction in search afforded to users can be applied to address several outstanding issues in mobile and ubiquitous user interaction including: limited feedback bandwidth; minimal attention situations; and the need for ad-hoc spontaneous interoperation and dynamic reconfiguration of multiple devices. The application of Direct Combination to mobile and ubiquitous interaction allows the user to exploit objects in the environment to rapidly narrow down the range of interactions that need be considered (by system and user). Ambient Combination may thus be viewed as a new way of distributing the user interface in the environment. When the DC technique of pairwise combination is applicable, it can greatly lessen the demands on users for memorisation and interface navigation, and can facilitate the use of recognition as opposed to recall when it is necessary to specify unfamiliar commands. Direct Combination, when extended and adapted to fit the demands of mobile and ubiquitous HCI is referred to as Ambient Combination (AC). In this paper we present Ambient Combination through a series of interaction scenarios. We describe a prototype Ambient Combination system, and the results of using this prototype system in a number of scenarios. Brief notes are given on the architecture. We discuss the principle of subsumption that allows Direct Combination to stay out of the way of users when it is not useful. We briefly discuss how preliminary analysis of the new abstract achitecture suggests that Ambient Combination offers a new approach and new leverage in dealing with context-aware interactions. Almost all of the elements of Ambient Combination