In accessing large collections of digitized videos, it is often difficult to find both the appropriate video file and the portion of the video that is of interest. This paper describes a novel technique for determining keyframes that are different from each other and provide a good representation of the whole video. We use keyframes to distinguish videos from each other, to summarize videos, and to provide access points into them. The technique can determine any number of keyframes by clustering the frames in a video and by selecting a representative frame from each cluster. Temporal constraints are used to filter out some clusters and to determine the representative frame for a cluster. Desirable visual features can be emphasized in the set of keyframes. An application for browsing a collection of videos makes use of the keyframes to support skimming and to provide visual summaries.

We describe a genetic segmentation algorithm for video. This algorithm operates on segments of a string representation. It is similar to both classical genetic algorithms that operate on bits of a string and genetic grouping algorithms that operate on subsets of a set. For evaluating segmentations, we define similarity adjacency functions, which are extremely expensive to optimize with traditional methods. The evolutionary nature of genetic algorithms offers a further advantage by enabling incremental segmentation. Applications include video summarization and indexing for browsing, plus adapting to user access patterns.

We describe a genetic segmentation algorithm for image data streams and video. This algorithm operates on segments of a string representation. It is similar to both classical genetic algorithms that operate on bits of a string and genetic grouping algorithms that operate on subsets of a set. It employs a segment fair crossover operation. For evaluating segmentations, we define similarity adjacency functions, which are extremely expensive to optimize with traditional methods. The evolutionary nature of genetic algorithms offers a further advantage by enabling incremental segmentation. Applications include browsing and summarizing video and collections of visually rich documents, plus a way of adapting to user access patterns.

We describe a way to make a hypermedia meeting record from multimedia meeting documents by automatically generating links through image matching. In particular, we look at video recordings and scanned paper handouts of presentation slides with ink annotations. The algorithm that we employ is the Discrete Cosine Transform (DCT). Interactions with multipath links and paper interfaces are discussed.

Much of hypertext narrative relies on links to shape a reader's interaction with the text. But links may be too limited to express ambiguity, imprecision, and entropy, or to admit new modes of participation short of full collaboration. We use an e-book form to explore the implications of freeform annotation-based interaction with hypertext narrative. Readers' marks on the text can be used to guide navigation, create a persistent record of a reading, or to recombine textual elements as a means of creating a new narrative. In this paper, we describe how such an experimental capability was created on top of XLibris, a next generation e-book, using Forward Anywhere as the hypernarrative. We work through a scenario of interaction, and discuss the issues the work raises

We present and interactive system that allows a user to locate regions of video that are similar to a video query. Thus segments of video can be found by simply providing an example of the video of interest. The user selects a video segment for the query from either a static frame-based interface or a video player. A statistical model of the query is calculated on-the-fly, and is used to find similar regions of video. The similarity measure is based on a Gaussian model of reduced frame image transform coefficients. Similarity in a single video is displayed in the Metadata Media Player. The player can be used to navigate through the video by jumping between regions of similarity. Similarity can be rapidly calculated for multiple video files as well. These results are displayed in MBase, a Web-based video browser that allows similarity in multiple video files to be visualized simultaneously.

This paper describes an application-independent tool called Anchored Conversations that brings together text-based conversations and documents. The design of Anchored Conversations is based on our observations of the use of documents and text chats in collaborative settings. We observed that chat spaces support work conversations, but they do not allow the close integration of conversations with work documents that can be seen when people are working together face-to-face. Anchored Conversations directly addresses this problem by allowing text chats to be anchored into documents. Anchored Conversations also facilitates document sharing; accepting an invitation to an anchored conversation results in the document being automatically uploaded. In addition, Anchored Conversations provides support for review, catch-up and asynchronous communications through a database. In this paper we describe motivating fieldwork, the design of Anchored Conversations, a scenario of use, and some preliminary results from a user study.

This paper presents a method for generating compact pictorial summarizations of video. We developed a novel approach for selecting still images from a video suitable for summarizing the video and for providing entry points into it. Images are laid out in a compact, visually pleasing display reminiscent of a comic book or Japanese manga. Users can explore the video by interacting with the presented summary. Links from each keyframe start video playback and/or present additional detail. Captions can be added to presentation frames to include commentary or descriptions such as the minutes of a recorded meeting. We conducted a study to compare variants of our summarization technique. The study participants judged the manga summary to be significantly better than the other two conditions with respect to their suitability for summaries and navigation, and their visual appeal.

S. Ichimura, L. Nelson, E.R. Pedersen.

Recently, physicists and computer scientists have realized that not only do our ideas about computing rest on only partly accurate principles, but they miss out on a whole class of computation. Quantum physics offers powerful methods of encoding and manipulating information that are not possible within a classical framework. The potential applications of these quantum information processing methods include provably secure key distribution for cryptography, rapid integer factoring, and quantum simulation.

J. Cassell, J. Sullivan, S. Prevost, and E. Churchill (Eds.).

The development of tools to support synchronous communications between non-collocated colleagues has received considerable attention in recent years. Much of the work has focused on increasing a sense of co-presence between interlocutors by supporting aspects of face-to-face conversations that go beyond mere words (e.g. gaze, postural shifts). In this regard, a design goal for many environments is the provision of as much media-richness as possible to support non-collocated communication. In this paper we present results from our most recent interviews studying the use of a text-based virtual environment to support work collaborations. We describe how such an environment, though lacking almost all the visual and auditory cues known to be important in face-to-face conversation, has played an important role in day-to-day communication. We offer a set of characteristics we feel are important to the success of this text-only tool and discuss issues emerging from its long-term use.