Introducing Selective Undo Features in a Collaborative Editor

Undo is an important functionality of editors. Selective undo is widely regarded as an important feature for collaborative editing. However, even after nearly three decades of active research and development, there is still no practical support of selective undo for collaborative editing. This paper introduces the selective undo features that we have implemented as part of a collaborative editing subsystem in the GNU Emacs text editor

Scalable XML Collaborative Editing with Undo

Commutative Replicated Data-Type (CRDT) is a new class of algorithms that ensure scalable consistency of replicated data. It has been successfully applied to collaborative editing of texts without complex concurrency control. In this paper, we present a CRDT to edit XML data. Compared to existing approaches for XML collaborative editing, our approach is more scalable and handles all the XML editing aspects : elements, contents, attributes and undo. Indeed, undo is recognized as an important feature for collaborative editing that allows to overcome system complexity through error recovery or collaborative conflict resolution.Le type de données répliqué commutatives (CRDT) est une nouvelle classe d'algorithmes qui assurent la cohérence des données répliquées tout en passant à l'échelle. Il a été appliqué avec succès à l'édition collaborative de textes sans mécanisme de contrôle de la concurrence complexe. Dans cet article, nous présentons un CRDT pour éditer des données XML. Par rapport aux approches existantes pour l'édition collaborative d'XML, notre approche offre un meilleur passage à l'échelle et gère tous les aspects de l'édition de document XML: éléments, le contenu, les attributs et l'annulation. En effet, l'annulation est reconnue comme un élément important pour l'édition collaborative qui permet de surmonter la complexité du système de collaboration grâce à la récupération d'erreur ou de résolution des conflits

Design of an UNDO framework

This paper sets out to provide a highly automated mechanism for an undo process that can be easily built into a new or existing system. Our proposal is based on the observation that it is not necessary to store the state of objects in memory, or the commands executed by the system to perform an undo, but it is sufficient to store the input data. This greatly simplifies the design process and undo encapsulate most of the functionality into a framework similar to those existing in many object oriented programmingVI Workshop Ingeniería de Software (WIS)Red de Universidades con Carreras en Informática (RedUNCI

Social Structure and Mechanisms of Collective Production: Evidence from Wikipedia

In my dissertation I propose three counterintuitive social mechanisms to alleviate the risk that collective production will fail to maintain participant involvement and respond to demand. My first study, based on a panel dataset of edits and views of articles in the English Wikipedia, shows that, although collective production lacks a price-like mechanism to estimate demand for the goods it produces, consumers’ contributions act as such a signal to expert producers. In the second paper I examine the theory that collective production participation is greatest when social norms of collaboration are obeyed. Using a large panel dataset of production networks and normrelated behavior in Wikipedia, I show that social norm infringement is not completely detrimental to participation because norm enforcement increases the likelihood that the beneficiary producer continues participating. In my third paper, I rely on interviews with experienced Wikipedia producers to examine whether producers’ ties to non-participants in collective production increase the likelihood of turnover, and whether producers’ embeddedness in collective production reduces turnover risk. Surprisingly, I find that producers with networks rich in ties to non-producers and with a task-oriented approach to collective production are those least likely to stop participating

Versioning in Interactive Systems

Dealing with past states of an interactive system is often difficult, and users often resort to unwieldy methods such as saving and naming multiple copies. Versioning tools can help users save and manipulate different versions of a document, but traditional tools designed for coding are often unsuitable for interactive systems. Supporting versioning in interactive systems requires investigation of how users think about versions and how they want to access and manipulate past states. We first surveyed users to understand what a ‘version’ means to them in the context of digital interactive work, and the circumstances under which they create new versions or go back to previous ones. We then built a versioning tool that can store versions using a variety of explicit and implicit mechanisms and shows a graphical representation of the version tree to allow easy inspection and manipulation. To observe how users used versions in different work contexts, we tested our versioning tool in two interactive systems – a game level editor and a web analysis tool. We report several new findings about how users of interactive systems create versions and use them as undo alternatives, exploring options, and planning future work. Our results show that versioning can be a valuable component that improves the power and usability of interactive systems. The new understanding that we gained about versioning in interactive environments by developing and evaluating our custom version tool can help us design more effective versioning tools for interactive systems

Design of an UNDO framework

This paper sets out to provide a highly automated mechanism for an undo process that can be easily built into a new or existing system. Our proposal is based on the observation that it is not necessary to store the state of objects in memory, or the commands executed by the system to perform an undo, but it is sufficient to store the input data. This greatly simplifies the design process and undo encapsulate most of the functionality into a framework similar to those existing in many object oriented programmingVI Workshop Ingeniería de Software (WIS)Red de Universidades con Carreras en Informática (RedUNCI

User Interfaces and Difference Visualizations for Alternatives

Designers often create multiple iterations to evaluate alternatives. Todays computer-based tools do not support such easy exploration of a design space, despite the fact that such support has been advocated. This dissertation is centered on this. I begin by investigating the effectiveness of various forms of difference visualizations and support for merging changes within a system targeted at diagrams with node and edge attributes. I evaluated the benefits of the introduced difference visualization techniques in two user studies. I found that the basic side-by-side juxtaposition visualization was not effective and also not well received. For comparing diagrams with matching node positions, participants preferred the side-by-side option with a difference layer. For diagrams with non-matching positions animation was beneficial, but the combination with a difference layer was preferred. Thus, the difference layer technique was useful and a good complement to animation. I continue by investigating if explicit support for design alternatives better supports exploration and creativity in a generative design system. To investigate the new techniques to better support exploration, I built a new system that supports parallel exploration of alternative designs and generation of new structural combinations. I investigate the usefulness of my prototype in two user studies and interviews. The results and feedback suggest and confirm that supporting design alternatives explicitly enables designers to work more creatively. Generative models are often represented as DAGs (directed acyclic graphs) in a dataflow programming environment. Existing approaches to compare such DAGs do not generalize to multiple alternatives. Informed by and building on the first part of my dissertation, I introduce a novel user interface that enables visual differencing and editing alternative graphsspecifically more than two alternatives simultaneously, something that has not been presented before. I also explore multi-monitor support to demonstrate that the difference visualization technique scales well to up to 18 alternatives. The novel jamming space feature makes organizing alternatives on a 23 monitor system easier. To investigate the usability of the new difference visualization method I conducted an exploratory interview with three expert designers. The received comments confirmed that it meets their design goals

Enhanced Visual Authoring Using Operation History

PhD thesisGraphical editors have introduced great flexibility to the designer's workflow, providing powerful digital tools and enabling the creation of complex and compelling designs. This thesis presents methods for improving these interactions by leveraging operation history. Much instrumentation and activity logging in software has been for the purpose of debugging, that is, for the benefit of the programmer or analyst. Our work addresses the mining of operation history for the benefit of the end user. We present three main contributions in this area. First, we introduce selection expansion, a method for facilitating the reuse of complex multiple-item selections by identifying items that are likely to be edited together. We then discuss an extension of this work, soft grouping, which gives users more control than standard selection and more flexibility than standard grouping. Finally, we present an interactive visualization of operation history, interactive storyboards, which enables in-context browsing and manipulation of operation history. We demonstrate these approaches in the context of vector graphics editing and present the results of pilot studies using our software implementation. While this thesis focuses on the usage patterns of graphic designers, many of the strategies could be generalized to other domains.Ph.D

Avoiding overload in multiuser online applications

One way to strengthen the bond between popular applications and their online user communities is to integrate the applications with their communities, so users are able to observe and communicate with other users. The result of this integration is a Multiuser Online Application (MOA). The problem studied in this thesis is that MOA users and systems will be overloaded with information generated by large communities and complex applications. The solution investigated was to filter the amount of information delivered to users while attempting to preserve the benefits of dwelling in a MOA environment. This strategy was evaluated according to the amount of information it was capable of reducing and the effects as seen by MOA users. It was found that filtering could be used to substantially reduce the information exchanged by users while still providing users with the benefits of integrating application and community

Proceedings of the ECSCW'95 Workshop on the Role of Version Control in CSCW Applications

The workshop entitled "The Role of Version Control in Computer Supported Cooperative Work Applications" was held on September 10, 1995 in Stockholm, Sweden in conjunction with the ECSCW'95 conference. Version control, the ability to manage relationships between successive instances of artifacts, organize those instances into meaningful structures, and support navigation and other operations on those structures, is an important problem in CSCW applications. It has long been recognized as a critical issue for inherently cooperative tasks such as software engineering, technical documentation, and authoring. The primary challenge for versioning in these areas is to support opportunistic, open-ended design processes requiring the preservation of historical perspectives in the design process, the reuse of previous designs, and the exploitation of alternative designs. The primary goal of this workshop was to bring together a diverse group of individuals interested in examining the role of versioning in Computer Supported Cooperative Work. Participation was encouraged from members of the research community currently investigating the versioning process in CSCW as well as application designers and developers who are familiar with the real-world requirements for versioning in CSCW. Both groups were represented at the workshop resulting in an exchange of ideas and information that helped to familiarize developers with the most recent research results in the area, and to provide researchers with an updated view of the needs and challenges faced by application developers. In preparing for this workshop, the organizers were able to build upon the results of their previous one entitled "The Workshop on Versioning in Hypertext" held in conjunction with the ECHT'94 conference. The following section of this report contains a summary in which the workshop organizers report the major results of the workshop. The summary is followed by a section that contains the position papers that were accepted to the workshop. The position papers provide more detailed information describing recent research efforts of the workshop participants as well as current challenges that are being encountered in the development of CSCW applications. A list of workshop participants is provided at the end of the report. The organizers would like to thank all of the participants for their contributions which were, of course, vital to the success of the workshop. We would also like to thank the ECSCW'95 conference organizers for providing a forum in which this workshop was possible