* Recent years have witnessed significant progress in intelligent user interfaces. Emerging from the intersection of Al and human-computer interaction, research on intelligent user interfaces is experiencing a renaissance, both in the overall level of activity and in raw research achievements. Research on intelligent user interfaces exploits developments in a broad range of foundational Al work, ranging from knowledge representation and computational linguistics to planning and vision. Because intelligent user interfaces are designed to facilitate problem-solving activities where reasoning is shared between users and the machine, they are currently transitioning from the laboratory to applications in the workplace, home, and classroom.
This special issue on intelligent user interfaces features a panorama of projects that highlight recent advances in the state of the art. Most of these projects have been presented at the premiere forum for intelligent user interface (IUI) research, the International Conference on Intelligent User Interfaces. The articles in this issue share three common themes. First, they describe projects that explore the boundaries of the man-machine interface. As a result, they examine issues that span both Al and human-computer interaction (HCI). Second, the articles all describe implemented systems. Although IUI work is evolving a strong theoretical basis, much of the cuttingedge activities take an "experimental systems" approach that revolves around iterative design, implementation, and evaluation of IUls with human subjects. Third, the articles describe task-oriented IUIs, that is, lUIs designed to support a specific family of tasks such as planning or tutoring.
The issue opens with three articles that present long-term efforts to create "conversational" lUIs. The first article, by Chuck Rich, Candy Sidney, and Neal Lesh, describes a project at the Mitsubishi Electric Research Laboratory to create a collaborative IUI that exploits the metaphor of conversation. Based on a rich theory of collaborative discourse, the COLLAGEN project explores the complex theoretical and engineering issues in devising a fullscale application-independent framework for collaborative IUI. Second, James Allen and his colleagues describe their decade-long work on spoken dialogue interfaces. Illustrating their discussion with the TRAINS and TRIPS systems, they explore the complexities of spoken dialogue and present solutions that have evolved in their lab. Third, Art Graesser, Kurt VanLehn, and their colleagues describe the features of complex multiturn tutorial dialogues. They present the joint work under way in their laboratories on the AUTOTUTOR, ANDES, ATLAS, and wHY2 systems, perhaps the most sophisticated tutorial dialogue projects in the intelligent tutoring systems community.
The second half of the issue features four articles that take an agent-oriented approach to lUIs. …