Publications

FXPAL publishes in top scientific conferences and journals.

2000

An Introduction to Quantum Computing for Non-Physicists.

Publication Details
  • ACM Computing Surveys, Vol. 32(3), pp. 300 - 335
  • Sep 1, 2000

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Richard Feynman's observation that quantum mechanical effects could not be simulated efficiently on a computer led to speculation that computation in general could be done more efficiently if it used quantum effects. This speculation appeared justified when Peter Shor described a polynomial time quantum algorithm for factoring integers. In quantum systems, the computational space increases exponentially with the size of the system which enables exponential parallelism. This parallelism could lead to exponentially faster quantum algorithms than possible classically. The catch is that accessing the results, which requires measurement, proves tricky and requires new non-traditional programming techniques. The aim of this paper is to guide computer scientists and other non-physicists through the conceptual and notational barriers that separate quantum computing from conventional computing. We introduce basic principles of quantum mechanics to explain where the power of quantum computers comes from and why it is difficult to harness. We describe quantum cryptography, teleportation, and dense coding. Various approaches to harnessing the power of quantum parallelism are explained, including Shor's algorithm, Grover's algorithm, and Hogg's algorithms. We conclude with a discussion of quantum error correction.
Publication Details
  • In Multimedia Tools and Applications, 11(3), pp. 347-358, 2000.
  • Aug 1, 2000

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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.

Expanding a Tangible User Interface

Publication Details
  • In proceedings of DIS'2000, ACM Press, August 2000.
  • Aug 1, 2000
Publication Details
  • In Proceedings of IEEE International Conference on Multimedia and Expo, vol. III, pp. 1329-1332, 2000.
  • Jul 30, 2000

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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.
Publication Details
  • In Proceedings of the Genetic and Evolutionary Computation Conference, Morgan Kaufmann Publishers, pp. 666-673, 2000.
  • Jul 8, 2000

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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.
Publication Details
  • In Japan Hardcopy 2000, The Annual Conference of the Imaging Society of Japan. 6/12 6/14 2000.
  • Jun 12, 2000
Publication Details
  • In Proceedings of Hypertext '00, ACM Press, pp. 244-245, 2000.
  • May 30, 2000

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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.

Hypertext Interaction Revisited

Publication Details
  • In Proceedings of Hypertext '00, ACM Press, pp. 171-179, 2000
  • May 30, 2000

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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
Publication Details
  • In RIAO'2000 Conference Proceedings, Content-Based Multimedia Information Access, C.I.D., pp. 637-648, 2000.
  • Apr 12, 2000

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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.

Anchored Conversations. Chatting in the Context of a Document.

Publication Details
  • In CHI 2000 Conference Proceedings, ACM Press, pp. 454-461, 2000.
  • Mar 31, 2000

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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.
Publication Details
  • In CHI 2000 Conference Proceedings, ACM Press, pp. 185-192, 2000.
  • Mar 31, 2000

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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.

Beyond Bits: The Future of Quantum Information Processing.

Publication Details
  • IEEE Computer, pp. 38-45, January 2000.
  • Feb 1, 2000

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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.
1999
Publication Details
  • In Proceedings of GROUP '99 (Phoenix, AZ), ACM Press, 1999.
  • Nov 14, 1999

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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.
Publication Details
  • In Proceedings of ACM Multimedia '99, Orlando, Florida, November 1999.
  • Oct 30, 1999

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NoteLook is a client-server system designed and built to support multimedia note taking in meetings with digital video and ink. It is integrated into a conference room equipped with computer controllable video cameras, video conference camera, and a large display rear video projector. The NoteLook client application runs on wireless pen-based notebook computers. Video channels containing images of the room activity and presentation material are transmitted by the NoteLook servers to the clients, and the images can be interactively and automatically incorporated into the note pages. Users can select channels, snap in large background images and sequences of thumbnails, and write freeform ink notes. A smart video source management component enables the capture of high quality images of the presentation material from a variety of sources. For accessing and browsing the notes and recorded video, NoteLook generates Web pages with links from the images and ink strokes correlated to the video.
Publication Details
  • In Proceedings ACM Multimedia, (Orlando, FL) ACM Press, pp. 383-392, 1999.
  • Oct 30, 1999

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This paper presents methods for automatically creating pictorial video summaries that resemble comic books. The relative importance of video segments is computed from their length and novelty. Image and audio analysis is used to automatically detect and emphasize meaningful events. Based on this importance measure, we choose relevant keyframes. Selected keyframes are sized by importance, and then efficiently packed into a pictorial summary. We present a quantitative measure of how well a summary captures the salient events in a video, and show how it can be used to improve our summaries. The result is a compact and visually pleasing summary that captures semantically important events, and is suitable for printing or Web access. Such a summary can be further enhanced by including text captions derived from OCR or other methods. We describe how the automatically generated summaries are used to simplify access to a large collection of videos.
Publication Details
  • In Proceedings of ACM Multimedia '99, pp. 77-80, Orlando, Florida, November 1999
  • Oct 30, 1999

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This paper presents a novel approach to visualizing the time structure of music and audio. The acoustic similarity between any two instants of an audio recording is calculated and displayed as a two-dimensional representation. Similar or repeating elements are visually distinct, allowing identification of structural and rhythmic characteristics. Visualization examples are presented for orchestral, jazz, and popular music. Applications include content-based analysis and segmentation, as well as tempo and structure extraction.

Tools for Quantum Algorithms

Publication Details
  • Int.J.Mod.Phys. C10 (1999) 1347-1362
  • Oct 29, 1999

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We present efficient implementations of a number of operations for quantum computers. These include controlled phase adjustments of the amplitudes in a superposition, permutations, approximations of transformations and generalizations of the phase adjustments to block matrix transformations. These operations generalize those used in proposed quantum search algorithms.
Publication Details
  • In Proceedings of the Second International Workshop on Cooperative Buildings (CoBuild'99). Lecture Notes in Computer Science, Vol. 1670 Springer-Verlag, pp. 79-88, 1999.
  • Oct 1, 1999

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We describe a media enriched conference room designed for capturing meetings. Our goal is to do this in a flexible, seamless, and unobtrusive manner in a public conference room that is used for everyday work. Room activity is captured by computer controllable video cameras, video conference cameras, and ceiling microphones. Presentation material displayed on a large screen rear video projector is captured by a smart video source management component that automatically locates the highest fidelity image source. Wireless pen-based notebook computers are used to take notes, which provide indexes to the captured meeting. Images can be interactively and automatically incorporated into the notes. Captured meetings may be browsed on the Web with links to recorded video.
Publication Details
  • In Human-Computer Interaction INTERACT '99, IOS Press, pp. 458-465, 1999.
  • Aug 30, 1999

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In our Portholes research, we found that users needed to have a sense of being in public and to know who can see them (audience) and who is looking currently at them (lookback). Two redesigns of the Portholes display present a 3D theater view of the audience. Different sections display core team members, non-core team members and lookback. An experiment determined that people have strong preferences about audience information and how it should be displayed. Layout preferences are varied, but unfolding techniques and cluster analysis reveal that these preference perspectives fall into four groups of similar preferences.
Publication Details
  • In Human-Computer Interaction INTERACT '99, IOS Press, pp. 205-212, 1999.
  • Aug 30, 1999

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When reviewing collections of video such as recorded meetings or presentations, users are often interested only in an overview or short segments of these documents. We present techniques that use automatic feature analysis, such as slide detection and applause detection, to help locate the desired video and to navigate to regions of interest within it. We built a web-based interface that graphically presents information about the contents of each video in a collection such as its keyframes and the distribution of a particular feature over time. A media player is tightly integrated with the web interface. It supports navigation within a selected file by visualiz-ing confidence scores for the presence of features and by using them as index points. We conducted a user study to refine the usability of these tools.

From Reading to Retrieval: Freeform Ink Annotations as Queries

Publication Details
  • In Proceedings of ACM SIGIR 99, ACM Press, pp. 19-25, 1999.
  • Aug 15, 1999

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User interfaces for digital libraries tend to focus on retrieval: users retrieve documents online, but then print them out and work with them on paper. One reason for printing documents is to annotate them with freeform ink while reading. Annotation can help readers to understand documents and to make them their own. In addition, annotation can reveal readers' interests with respect to a particular document. In particular, it is possible to construct full-text queries based on annotated passages of documents. We describe an experiment that tested the effectiveness of such queries, as compared to relevance feedback query techniques. For a set of TREC topics and documents, queries derived from annotated passages produced significantly better results than queries derived from subjects' judgments of relevance.

Introducing a Digital Library Reading Appliance into a Reading Group.

Publication Details
  • In Proceedings of ACM Digital Libraries 99, ACM Press, pp. 77-84, 1999.
  • Aug 11, 1999

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How will we read digital library materials? This paper describes the reading practices of an on-going reading group, and how these practices changed when we introduced XLibris, a digital library reading appliance that uses a pen tablet computer to provide a paper-like interface. We interviewed group members about their reading practices, observed their meetings, and analyzed their annotations, both when they read a paper document and when they read using XLibris. We use these data to characterize their analytic reading, reference use, and annotation practices. We also describe the use of the Reader's Notebook, a list of clippings that XLibris computes from a reader's annotations. Implications for digital libraries stem from our findings on reading and mobility, the complexity of analytic reading, the social nature of reference following, and the unselfconscious nature of readers' annotations.

Palette: A Paper Interface for Giving Presentations.

Publication Details
  • In Proceeding of the CHI 99 Conference on Human Factors in Computing Systems, ACM Press, pp. 354-361, 1999.
  • May 18, 1999

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The Palette is a digital appliance designed for intuitive control of electronic slide shows. Current interfaces demand too much of our attention to permit effective computer use in situations where we can not give the technology our fullest concentration. The Palette uses index cards that are printed with slide content that is easily identified by both humans and computers. The presenter controls the presentation by directly manipulating the cards. The Palette design is based on our observation of presentations given in a real work setting. Our experiences using the system are described, including new practices (e.g., collaborative presentation, enhanced notetaking) that arise from the affordances of this new approach. This system is an example of a new interaction paradigm called tacit interaction that supports users who can spare very little attention to a computer interface.

NotePals: Lightweight Note Sharing by the Group, for the Group.

Publication Details
  • In Proceeding of the CHI 99 Conference on Human Factors in Computing Systems, ACM Press, pp. 338-345, 1999.
  • May 18, 1999

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NotePals is a lightweight note sharing system that gives group members easy access to each other's experiences through their personal notes. The system allows notes taken by group members in any context to be uploaded to a shared repository. Group members view these notes with browsers that allow them to retrieve all notes taken in a given context or to access notes from other related notes or documents. This is possible because NotePals records the context in which each note is created (e.g., its author, subject, and creation time). The system is "lightweight" because it fits easily into group members' regular note-taking practices, and uses informal, ink-based user interfaces that run on portable, inexpensive hardware. In this paper we describe NotePals, show how we have used it to share our notes, and present our evaluations of the system.

Face-to-Face Interfaces.

Publication Details
  • In CHI 99 Extended Abstracts, ACM Press, pp. 244-245, 1999.
  • May 18, 1999

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Recent work on the social nature of human-computer interactions [3] has prompted research on animated, anthropomorphic characters in user interfaces. Such interfaces may simplify user interactions by allowing them to use and interpret natural face-to-face communication techniques such as speech, gestures and facial expressions. We describe our initial implementation, a character that controls the A/V facilities in a state-of-the-art conference room, and outline the goals of our ongoing project.

Printertainment: Printing With Interactive Cover Sheets.

Publication Details
  • In CHI 99 Extended Abstracts, ACM Press, pp. 240-241, 1999.
  • May 18, 1999

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We explored a new type of user interface, interactive cover sheets: computer forms laid out on the banner pages of print jobs that people can mark on, scan back into a multifunction printer/scanner, and use as input to applications. Cover sheets are commonly strewn around printer rooms; with interactivity, they can let people see what others have to say, add their own comments, or play games, all while waiting for their print jobs. We designed three prototype applications and deployed them briefly in our research lab. We found that interactive cover sheets can be very appealing, that the sheets must be designed so that people can still identify these pages as cover sheets, and that the slow interaction cycle favors asynchronous applications.
Publication Details
  • In Proceedings of the International Conference on Acoustics, Speech, and Signal Processing (Phoenix, AZ), vol. 6, pp. 3041-3044, 1999.
  • Mar 14, 1999

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This paper presents methods of generating compact pictorial summarizations of video. By calculating a measure of shot importance video can be summarized by de-emphasizing or discarding less important information, such as repeated or common scenes. In contrast to other approaches that present keyframes for each shot, this measure allows summarization by presenting only the most important shots. Selected keyframes can also be resized depending on their relative importance. We present an efficient packing algorithm that constructs a pictorial representation from differently-sized keyframes. This results in a compact and visually pleasing summary reminiscent of a comic book.
Publication Details
  • In Proceedings of the International Conference on Acoustics, Speech, and Signal Processing (Phoenix, AZ), vol. 6, pp. 3453-3456, 1999.
  • Mar 14, 1999

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This paper describes a technique for automatically creating an index for handwritten notes captured as digital ink. No text recog-nition is performed. Rather, a dictionary of possible index terms is built by clustering groups of ink strokes corresponding roughly to words. Terms whose distribution varies significantly across note pages are selected for the index. An index page containing the index terms is created, and terms are hyper-linked back to their original location in the notes. Further, index terms occurring in a note page are highlighted to aid browsing.
Publication Details
  • In Proceedings of the International Conference on Acoustics, Speech, and Signal Processing (Phoenix, AZ), vol. 6, pp. 3045-3048, 1999.
  • Mar 14, 1999

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This paper describes techniques for classifying video frames using statistical models of reduced DCT or Hadamard transform coefficients. When decimated in time and reduced using truncation or principal component analysis, transform coefficients taken across an entire frame image allow rapid modeling, segmentation, and similarity calculation. Unlike color-histogram metrics, this approach models image composition and works on grayscale images. Modeling the statistics of the transformed video frame images gives a likelihood measure that allows video to be segmented, classified, and ranked by similarity for retrieval. Experiments are presented that show an 87% correct classification rate for different classes. Applications are presented including a content-aware video browser.
Publication Details
  • In Proceedings of the International Conference on Acoustics, Speech, and Signal Processing (Phoenix, AZ), vol. 6, pp. 3029-3032, 1999.
  • Mar 14, 1999

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This paper describes a method for finding segments in video-recorded meetings that correspond to presentations. These segments serve as indexes into the recorded meeting. The system automatically detects intervals of video that correspond to presentation slides. We assume that only one person speaks during an interval when slides are detected. Thus these intervals can be used as training data for a speaker spotting system. An HMM is automatically constructed and trained on the audio data from each slide interval. A Viterbi alignment then resegments the audio according to speaker. Since the same speaker may talk across multiple slide intervals, the acoustic data from these intervals is clustered to yield an estimate of the number of distinct speakers and their order. This allows the individual presentations in the video to be identified from the location of each presenter's speech. Results are presented for a corpus of six meeting videos.
Publication Details
  • In Proceedings of the International Joint Conference on Work Activities Coordination and Collaboration, pp. 147-156, 1999.
  • Feb 22, 1999

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In many hierarchical companies, reports from several independent groups must be merged to form a single, company-wide report. This paper describes a process and system for creating and structuring such reports and for propagating contributions up the organization. The system has been in regular use, in-house, by about 30 users for over a year to create monthly status reports. Our experiences indicate that it is possible to change a monthly reporting practice so that the system is easy to use, improves the quality of the written report, fosters collaboration across projects and creates a corporate memory for the company. These results were achieved as a consequence of our design effort to directly support the hierarchical and collaborative process of creating and assembling the report within the organization. User feedback has led to many improvements in the usability and functionality of the system. Further enhancements using information retrieval and text summarization techniques are in progress.
Publication Details
  • In Proceedings of the Thirty-Second Annual Hawaii International Conference on System Sciences (HICSS-32), R. Sprague, Jr., editor, 1999.
  • Feb 5, 1999

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This is a critical view of the hypothesis that better access to a broader repertoire of media resources will significantly enhance our ability to communicate more effectively. It begins by laying down a foundation of some basic principles concerning the nature of knowledge creation. This foundation is framed in a manner that involves the potential relevance of two particularly creative activities, storytelling and making jazz. This foundation provides the basis for a critical examination of several media-rich presentations that were delivered at the Institute for the Future Outlook Exchange in November of 1997, since these presentations actually pertained to the practices of digital storytelling and jamming. This critique is followed by a more detailed examination of what we may learn from jazz if we wish to invoke it as a metaphor for knowledge creation. The report then concludes by discussing the implications of these observations for a new world of work experiences in which knowledge creation is a critical element.
Publication Details
  • In Proceedings of the Thirty-Second Annual Hawaii International Conference on System Sciences (HICSS-32), R. Sprague, Jr., editor, 1999.
  • Feb 5, 1999

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The genre of mathematics writing has several distinctive features that point to some of the weaknesses of current digital documents. Some of these weaknesses are surprising. While it might be expected that the importance of formatting and special symbols in mathematics writing would pose challenges for digital documents, the linked, chunked style of mathematics writing, with its Theorems, Lemmas, Corollaries and Remarks explicitly referring to each other, resembles standard hypertext so closely that one would expect that mathematics writing would take well to online hypertext form. It does not. This failure points to deficiencies in our understanding of the true strengths and weaknesses of digital documents. This paper describes mathematics writing, with particular emphasis on features of interest with respect to digital documents. The difficulties in producing effective digital mathematics documents are then examined and used as a basis for talking about general challenges for digital documents. The paper then discusses strengths of digital documents and some of the problems that need to be overcome before digital documents can live up to claims made for them. It also examines some of the misguided claims, such as superior support for non-linearity, that are commonly made for digital documents, explains why these claims are unwarranted, and speculates on why the claims have been made anyway. Suggestions are then given as to what the true benefits of digitization are, including performing computations on text, flexible control of time, and better support for hiding information. The paper concludes with a list of questions whose answers are critical to understanding the capabilities, and therefore the future, of digital documents.

Distributed Research Teams: Meeting Asynchronously in Virtual Space.

Publication Details
  • In Proceedings of the Thirty-second Annual Hawaii International Conference on System Sciences (Wailea, Hawaii, January 1999).
  • Feb 1, 1999

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As computer networks improve, more social and work interactions are carried out "virtually" by geographically separated group members. In this paper we discuss the design of a tool, PAVE, to support remote work interactions among colleagues in different time zones. PAVE extends a 2D graphical MOO and supports synchronous and asynchronous interactions. PAVE logs and indexes activities in the space. This capture facility enables playback and augmentation of meeting interactions by non-collocated group members. Thus, members can participate asynchronously in meetings they could not attend in real time, not just review them.