. The proliferation ofcomputing into the physical world promises more than the ubiquitous availability of computing infrastructure; it suggests new paradigms of interaction inspired by constant access to information and computational capabilities. For the past decade, applicationdriven research in ubicomp has pushed three interaction themes: natural interfaces, context-aware applications, and automated capture and access. To chart a course for future research in ubiquitous computing, we review the accomplishments of these efforts and point to remaining research challenges. Research in ubiquitous computing implicitly requires addressing some notion of scale; whether in the number and type of devices, the physical space of distributed computing or the number of people using a system. We posit a new area of applications research, everyday computing, focussed on scaling interaction with respect to time. Just as pushing the availability of computing away from the traditional desktop fun...

g the course of a task. Many of these applications involve the collection, comprehension, 88 August 1995/Vol. 38, No. 8 COMMUNICATIONS OF THE ACM Catherine C. Marshall Frank M. Shipman III Spatial Hypertext: Designing for Change ypertext, 1 in its most general sense, allows content to appear in different contexts. The immediate setting in which readers encounter a specific segment of material then changes from reading to reading or from reader to reader. Authors collect and structure materials to reflect their own understanding or in anticipation of readers' possible interests, needs, or ability to comprehend the substrate of interrelated content. 1 We use the term hypertext broadly, to cover both textual and multimedia content. Node A Node A Node D Node E Node C Node B Node A and interpretation of diverse materials

This paper describes the concept of Time-Machine Computing (TMC), a time-centric approach to organizing information on computers. A system based on Time-Machine Computing allows a user to visit the past and the future states of computers. When a user needs to refer to a document that he/she was working on at some other time, he/she can travel in the time dimension and the system restores the computer state at that time. Since the user's activities on the system are automatically archived, the user's daily workspace is seamlessly integrated into the information archive. The combination of spatial information management of the desktop metaphor and time traveling allows a user to organize and archive information without being bothered by folder hierarchies or the file classification problems that are common in today's desktop environments. TMC also provides a mechanism for linking multiple applications and external information sources by exchanging time information. This paper describes ...

Our goal is to provide tools to support working meetings on an electronic whiteboard, called Tivoli. This paper de- scribes how we have integrated structured "domain objects" into the whiteboard environment. Domain objects represent the subject matter of meetings and can be exchanged between Tivoli and group databases. Domain objects can be tailored to produce meeting tools that are finely tuned to meeting practices. We describe the facility for tailoring and managing domain objects and the user interface techniques for blending these into the whiteboard environment. We show examples of both specific and generic meeting tools crafted from domain objects, and we describe a long-term case study in which these tools support an ongoing work process.

The historical development of hypermedia systems can be characterized as a series of successive abstractions of functionality away from the "core " hypermedia server, often resulting in a new open layer in the hypermedia environment architecture. Recently, this trend of abstraction has been applied to the hypermedia server itself, replacing the notion of a single, closed hypermedia server with an open layer of structure servers. This newest development brings with it a new set of challenges and research issues for open hypermedia researchers. In this paper, we discuss these issues, review some of our collective applicable experience with contemporary open hypermedia systems and other work, and point out some of the more pressing and intriguing open questions that we feel are facing open hypermedia researchers today. We also examine the "split" in the current hypermedia research community between "system " and "domain " researchers and the still-present need for interoperability among systems, and discuss why any attempt to address the issues we discuss in this paper must account for these observations.

Hypertext began as a vision of interconnected reference materials [Bush 1945] and literature [Robertson 1998]. These early visions were joined by working systems that supported link-based navigation among documents as well as branching points within (hyper)documents [Engelbart 1984]. As the use of hypertext systems became more widespread, researchers realized that readers could become confused or lost as they navigated large networks

Scholarly hypertexts involve argument and explicit selfquestioning, and can be distinguished from both informational and literary hypertexts. After making these distinctions the essay presents general principles about attention, some suggestions for self-representational multi-level structures that would enhance scholarly inquiry, and a wish list of software capabilities to support such structures. The essay concludes with a discussion of possible conflicts between scholarly inquiry and hypertext. KEYWORDS: Hypertext rhetoric, argument, scholarship, typed nodes, typed links, self-representation 1 SCHOLARLY HYPERTEXTS If we classified all the hypertexts in use, most would be networks of information that are either in the process of being organized or are being consulted. Tremendous effort has gone into discovering manual and automatic linking strategies to organize information and make it efficiently manipulable. On the other hand, there are literary hypertexts whose goals differ fro...

Our goal is to provide tools to support working meetings on an electronic whiteboard, called Tivoli. This paper describes how we have integrated structured domain objects, which represent the subject matter of meetings, into the freeform whiteboard environment. Domain objects can be tailored to produce meeting tools that are finely tuned to meeting practices. We describe the language for defining domain objects and show examples of meeting tools that have been built with the language. We show that the system can interpret the spatial relationships of domain objects on the whiteboard to encode the meanings of the spatial arrangements, and we describe the computational mechanisms. We discuss some of the design principles for tailoring gestures for domain objects. Finally, we enumerate the techniques we have used to integrate the structured objects into the freeform whiteboard environment.

This paper presents Garnet, a novel spatial hypertext interface to a digital library. Garnet supports both information structuring – via spatial hypertext – and traditional information seeking – via a digital library. A user study of Garnet is reported, together with an analysis of how the organizing work done by users in a spatial hypertext workspace could support later information seeking. The use of Garnet during the study is related to both digital library and spatial hypertext research. Spatial hypertexts support the detection of implicit document groups in a user’s workspace. The study also investigates the degree of similarity found in the full text of documents within such document groups. Categories and Subject Descriptors H.5.4 [Hypertext/Hypermedia]: User issues

Spatial layout is frequently used for managing loosely organized information, such as desktop icons and digital ink. To help users organize this type of information efficiently, we propose an interface for manipulating spatial aggregations of objects. The aggregated objects are automatically recognized as a group, and the group structure is visualized as a two-dimensional bubble surface that surrounds the objects. Users can drag, copy, or delete a group by operating on the bubble. Furthermore, to help pick out individual objects in a dense aggregation, the system spreads the objects to avoid overlapping when requested. This paper describes the design of this interface and its implementation. We tested our technique in icon grouping and ink relocation tasks and observed improvements in user performance. ACM Classification: H5.2 [Information interfaces and presentation]: User Interfaces – Graphical user interfaces.