This article describes two years of experience with a research prototype for personalizing shared workplace devices such as projectors, public displays, and multi-function copiers. The system combines users' networked resources-or "personal information clouds"—with device-specific user interfaces for performing common device tasks. We developed and compared personal interfaces that are embedded (i.e., integrated or co-located with the shared device) and portable (i.e., accessible via personal devices such as mobile phones and PDAs). Our experience indicates that a little personalization can go a long way toward improving user friendliness, efficiency, and capabilities of shared document devices, helping them "weave themselves into the fabric of everyday life". We also gained important insights into subtle differences between embedded and portable approaches to ubiquitous computing systems.

In this paper we present recent developments in discourse theory and parsing under the Linguistic Discourse Model framework, a semantic theory of discourse structure. We give a novel approach to the problems of discourse segmentation based on discourse semantics and sketch a limited but robust approach to symbolic discourse parsing based on syntactic, semantic and lexical rules. To demonstrate the utilioty of the system in a real application, we briefly describe the architecture of the PALSUMM System, a symbolic smmarization system being developed at FX Palo Alto Laboratory that uses discourse structures constructed usding the theory otlined to summarize written English texts.

It is challenging to browse multimedia on mobile devices with small displays. We present MiniMedia Surfer, a prototype application for interactively searching a multimedia collection for video segments of interest. Transparent layers are used to support browsing subtasks: keyword query, exploration of results through keyframes, and playback of video. This layered interface smoothly blends the key tasks of the browsing process and deals with the small screen size. During exploration, the user can adjust the transparency levels of the layers using pen gestures. Details of the video segments are displayed in an expandable timeline that supports gestural interaction.

The Plasma Posters are large screen, digital, interactive posterboards designed for informal content sharing within teams, groups, organizations and communities. Leveraging the fact that the physical world is often used as a canvas for asynchronous information exchange via paper fliers and posters, the Plasma Posters provide a platform for sharing interactive digital content in public places. People serendipitously encounter multimedia content usually only encountered from the desktop, while going about their daily business. In this paper we describe the Plasma Poster interface in detail, and offer and overview of the underlying information authoring, parsing, storage, distribution and publishing infrastructure, the Plasma Poster Network. We report qualitative and quantitative data collected over 14 months of use that demonstrate the Plasma Posters have become an integral part of information sharing within our organization. We conclude the paper by reflecting on the patterns of adoption, and speculate on factors that have contributed to the system's success. Finally we briefly describe three other installations of the Plasma Poster Network and new interfaces that have been designed.

Collaborative note taking enables students in a class to take notes on their PDAs and share them with their "study group" in real-time. Students receive instructor's slides on their PDAs as they are displayed by the instructor. As the individual members of the group take notes pertaining to the slide being presented, their notes are automatically sent to all members of the group. In addition, to reduce their typing, students can use text they receive from other students and from the instructors slides to construct their notes. This system has been used in actual practice for a graduate level course on wireless mobile computing. In developing this system, special attention has been paid to the task of inputting text on PDAs, efficient use of the screen real estate, dynamics among students, privacy and ease of use issues.

In this paper, we present a framework for analyzing video using self-similarity. Video scenes are located by analyzing inter-frame similarity matrices. The approach is flexible to the choice of both feature parametrization and similarity measure and it is robust because the data is used to model itself. We present the approach and its application to shot boundary detection.

Our physical environment is increasingly filled with multimedia content on situated, community public displays. We are designing methods for people to post and acquire digital information to and from public digital displays, and to modify and annotate previously posted content to create publicly observable threads. We support in-the-moment and on-site "person-to-place-to-people-to-persons" content interaction, annotation, augmentation and publication. We draw design inspiration from field work observations of how people remove, modify and mark up paper postings. We present our initial designs in this arena, and some initial user reactions.

With the acceleration of technological development we are reaching the point where our systems and their user interfaces become to some degree outdated 'legacy systems' as soon as they are released. This raises the question of how can we maintain, extend, override, and adapt these systems while preserving what people depend on in them? In this paper we describe an approach for dynamically restructuring user interfaces into a set of communicating processes that 1) provide methods for changing their appearance, behavior, and state; and 2) report their proposed state changes so that other processes may override their actions in updating themselves to a new state. We do this for both new and wrapped legacy user interface components, thereby allowing us to repurpose user interfaces for our evolving needs. We describe how this approach has been successfully used in rapidly creating and deploying interfaces that repurpose content for new appearances and behaviors.

Blurring the boundary between the digital and physical in social activity spaces helps blend - and motivate - online and face-to-face community participation. This paper discusses two experimental installations of large screen displays at conferences - CHI 2002 and CSCW 2002. The displays offered a window in the conference arena onto online community information.

People routinely rely on physical and electronic systems to remind themselves of details regarding personal and organizational contacts. These systems include rolodexes, directories and contact databases. In order to access details regarding contacts, users must typically shift their attention from tasks they are performing to the contact system itself in order to manually look-up contacts. This paper presents an approach for automatically retrieving contacts based on users' current context. Results are presented to users in a manner that does not disrupt their tasks, but which allows them to access contact details with a single interaction. The approach promotes the discovery of new contacts that users may not have found otherwise and supports serendipity.

This edited volume brings together projects funded by, or related to, the European i3 initiative. Projects address the design, development and use of rich, digital information spaces for collocated and distributed collaboration.

Public and situated display technologies have an important impact on individual and social behaviour and present us with particular interesting new design considerations and challenges. While there is a growing body of research exploring these design considerations and social impacts this work remains somewhat disparate, making it difficult to assimilate in a coherent manner. This book brings together the perspective of key researchers in the area of public and situated display technology. The chapters detail research representing the social, technical and interactional aspects of public and sitauted display technologies. The underlying concern common to these chapters is how these displays can be best designed for collaboration, coordination, community building and mobility.

The sharing of digital materials within online communities has increased significantly in recent years. Our work focuses on promoting community information sharing in public spaces using large screen, interactive, digital poster boards called the Plasma Posters. In this chapter we first describe our fieldwork-led, iterative design process, and elaborate a number of design guidelines that resulted. Following this, the design and development of the Plasma Posters themselves and the underlying network infrastructure is discussed. Finally, we present results from qualitative and quantitative evaluations over the course of a ten-month deployment of three Plasma Posters within our own organization, a software research community made up of technologists and designers. We conclude with observations regarding ergonomic, social and other factors that were raised during the design and deployment and offer reflections on factors in the success of this deployment.

We describe a novel interface for presenting interactive content on public digital bulletin boards. Inspired by paper fliers on physical bulletin boards, posted content is displayed using 3D virtual fliers attached to a virtual corkboard by virtual pushpins. Fliers appear in different orientations, creating an attractive, informal look, and have autonomous behaviors like fluttering in the wind. Passers-by can rotate, move and fold fliers; they can also interact with fliers' live content. Flier content is streamed from a server and represented by the system on large screen displays using a real-time cloth simulation algorithm. We describe our prototype, and offer the results of an initial evaluative user study.

We present similarity-based methods to cluster digital photos by time and image content. The approach is general, unsupervised, and makes minimal assumptions regarding the structure or statistics of the photo collection. We present results for the algorithm based solely on temporal similarity, and jointly on temporal and content-based similarity. We also describe a supervised algorithm based on learning vector quantization. Finally, we include experimental results for the proposed algorithms and several competing approaches on two test collections.

We present a system that allows remote and local participants to control devices in a meeting environment using mouse or pen based gestures "through" video windows. Unlike state-of-the-art device control interfaces that require interaction with text commands, buttons, or other artificial symbols, our approach allows users to interact with devices through live video of the environment. This naturally extends our video supported pan/tilt/zoom (PTZ) camera control system, by allowing gestures in video windows to control not only PTZ cameras, but also other devices visible in video images. For example, an authorized meeting participant can show a presentation on a screen by dragging the file on a personal laptop and dropping it on the video image of the presentation screen. This paper presents the system architecture, implementation tradeoffs, and various meeting control scenarios.

To simplify the process of editing interactive video, we developed the concept of "detail-on-demand" video as a subset of general hypervideo. Detail-on-demand video keeps the authoring and viewing interfaces relatively simple while supporting a wide range of interactive video applications. Our editor, Hyper-Hitchcock, provides a direct manipulation environment in which authors can combine video clips and place hyperlinks between them. To summarize a video, Hyper-Hitchcock can also automatically generate a hypervideo composed of multiple video summary levels and navigational links between these summaries and the original video. Viewers may interactively select the amount of detail they see, access more detailed summaries, and navigate to the source video through the summary.

In this paper, we describe how a detail-on-demand representation for interactive video is used in video summarization. Our approach automatically generates a hypervideo composed of multiple video summary levels and navigational links between these summaries and the original video. Viewers may interactively select the amount of detail they see, access more detailed summaries, and navigate to the source video through the summary. We created a representation for interactive video that supports a wide range of interactive video applications and Hyper-Hitchcock, an editor and player for this type of interactive video. Hyper-Hitchcock employs methods to determine (1) the number and length of levels in the hypervideo summary, (2) the video clips for each level in the hypervideo, (3) the grouping of clips into composites, and (4) the links between elements in the summary. These decisions are based on an inferred quality of video segments and temporal relations those segments.

The FXPAL Photo Application is designed to faciliate the organization of digital images from digital cameras and other sources through automated organization and intuitive user interfaces.

We demonstrate the use of detail-on-demand hypervideo in interactive training and video summarization. Detail-on-demand video allows viewers to watch short video segments and to follow hyperlinks to see additional detail. The player for detail-ondemand video displays keyframes indicating what links are available at each point in the video. The Hyper-Hitchcock authoring tool helps users create hypervideo by automatically dividing video into clips that can be combined in a direct manipulation interface. Clips can be grouped into composites and hyperlinks can be placed between clips and composites. A summarization algorithm creates multi-level hypervideo summaries from linear video by automatically selecting clips and placing links between them.

We present a framework for summarizing digital media based on structural analysis. Though these methods are applicable to general media, we concentrate here on characterizing repetitive structure in popular music. In the first step, a similarity matrix is calculated from inter-frame spectral similarity. Segment boundaries, such as verse-chorus transitions, are found by correlating a kernel along the diagonal of the matrix. Once segmented, spectral statistics of each segment are computed. In the second step, segments are clustered based on the pairwise similarity of their statistics, using a matrix decomposition approach. Finally, the audio is summarized by combining segments representing the clusters most frequently repeated throughout the piece. We present results on a small corpus showing more than 90% correct detection of verse and chorus segments.

This demonstration introduces UbiComp attendees to a system for content annotation and open-air, social blogging on interactive, publicly situated, digital poster boards using public and personal devices. We describe our motivation, a scenario of use, our prototype, and an outline of the demonstration.

As the Internet and related technologies for communication change, the role of communication in the conduct of business changes with it. Communication used to be viewed as a technical problem of separating signal from noise and managing bandwidth. Now it is a social matter in which negotiating differences in understanding among communicators is a primary business priority. Addressing this priority requires an understanding of how individuals interact in the course of their decision making activities. Using the work of Anthony Giddens as a point of departure, this paper views interaction in communication as consisting of three dimensions - meaning, authority, and trust. These three dimensions are used to identify new opportunities for advances in decision making technology that help deal with potential breakdowns in social interaction.

We present similarity-based methods to cluster digital photos by time and image content. This approach is general, unsupervised, and makes minimal assumptions regarding the structure or statistics of the photo collection. We describe versions of the algorithm using temporal similarity with and without content-based similarity, and compare the algorithms with existing techniques, measured against ground-truth clusters created by humans.