Direct Combination: A New User Interaction Principle for Mobile and Ubiquitous HCI

Abstract

Abstract. Direct Combination (DC) is a recently introduced user interaction principle. The principle (previously applied to desktop computing) can greatly reduce the degree of search, time, and attention required to operate user interfaces. We argue that Direct Combination applies particularly aptly to mobile computing devices, given appropriate interaction techniques, examples of which are presented here. The reduction in search afforded to users can be applied to address several 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. When Direct Combination is extended and adapted to fit the demands of mobile and ubiquitous HCI, we refer to it as Ambient Combination (AC). Direct Combination allows the user to exploit objects in the environment to narrow down the range of interactions that need be considered (by system and user). When the DC technique of pairwise or n-fold combination is applicable, it can greatly lessen the demands on users for memorisation and interface navigation. Direct Combination also appears to offers a new way of applying context-aware information. In this paper, we present Direct Combination as applied ambiently through a series of interaction scenarios, using an implemented prototype system.

A First Empirical Study of Direct Combination in a Ubiquitous Environment

“…We propose that a good principled basis for addressing this and related problems is the principle of Direct Combination [Holland & Oppenheim 1999;Holland et al 2002]. We will argue that Direct Combination allows the user interface to be made highly economical, and the amount of search required by the user to be reduced.…”

“…The principle of Direct Combination, with its associated interaction techniques and architecture is perhaps best introduced by means of an example. For reasons of memorability we will use an imaginary interaction scenario borrowed from Holland et al [2002] featuring a magic wand. Binsted [2000] has argued that imagined magic is a valuable tool when designing or analysing innovative interaction technologies.…”

“…In practical terms, viewed from the point of view of the user, the principle of Direct Combination [Holland & Oppenheim 1999;Holland et al 2002] can be stated as follows:…”

“…The principle of subsumption [Holland & Oppenheim 1999;Holland et al 2002] requires that DC should always include conventional interaction patterns as special cases -as illustrated below. To be scaleable and maintainable, appropriate supporting software architecture and analysis methods are required; both of which requirements now have well-founded solutions.…”

“…The problems are particularly acute when the search is performed on the move via mobile devices with small, resource-poor user interfaces. Typically users are forced to spend time and attention distracted from their main task, searching a sequence of screens and menus [Holland et al 2002]. The problem of supporting inter-operation in changing circumstances, especially in ubiquitous systems, is called the problem of spontaneous interaction.…”