James D. Thornton

VoCCN: voice-over content-centric networks

A variety of proposals call for a new Internet architecture focused on retrieving content by name, but it has not been clear that any of these approaches are general enough to support Internet applications like real-time streaming or email. We present a detailed description of a prototype implementation of one such application -- Voice over IP (VoIP) -- in a content-based paradigm. This serves as a good example to show how content-based networking can offer advantages for the full range of Internet applications, if the architecture has certain key properties.

Extending document management systems with user-specific active properties

Document properties are a compelling infrastructure on which to develop document management applications. A property-based approach avoids many of the problems of traditional heierarchical storage mechanisms, reflects document organizations meaningful to user tasks, provides a means to integrate the perspectives of multiple individuals and groups, and does this all within a uniform interaction framework. Document properties can reflect not only categorizations of documents and document use, but also expressions of desired system activity, such as sharing criteria, replication management, and versioning. Augmenting property-based document management systems with active properties that carry executable code enables the provision of document-based services on a property infrastructure. The combination of document properties as a uniform mechanism for document management, and active properties as a way of delivering document services, represents a new paradigm for document management infrastructures. The Placeless Documents system is an experimental prototype developed to explore this new paradigm. It is based on the seamless integration of user-specific, active properties. We present the fundamental design approach, explore the challenges and opportunities it presents, and show our architectures deals with them.

Networking named content

Current network use is dominated by content distribution and retrieval yet current networking protocols are designed for conversations between hosts. Accessing content and services requires mapping from the what that users care about to the networks where. We present Content-Centric Networking (CCN) which uses content chunks as a primitive---decoupling location from identity, security and access, and retrieving chunks of content by name. Using new approaches to routing named content, derived from IP, CCN simultaneously achieves scalability, security, and performance. We describe our implementation of the architectures basic features and demonstrate its performance and resilience with secure file downloads and VoIP calls.

Revisiting the visit:: understanding how technology can shape the museum visit

This paper reports findings from a study of how a guidebook was used by pairs of visitors touring a historic house. We describe how the guidebook was incorporated into their visit in four ways: shared listening, independent use, following one another, and checking in on each other. We discuss how individual and groupware features were adopted in support of different visiting experiences, and illustrate how that adoption was influenced by social relationships, the nature of the current visit, and any museum visiting strategies that the couples had. Finally, we describe how the guidebook facilitated awareness between couples, and how awareness of non-guidebook users (strangers) influenced use.

Social TV: Designing for Distributed, Sociable Television Viewing

Media research has shown that people enjoy watching television as a part of socializing in groups. However, many constraints in daily life limit the opportunities for doing so. The Social TV project builds on the increasing integration of television and computer technology to support sociable, computer-mediated group viewing experiences. In this article, we describe the initial results from a series of studies illustrating how people interact in front of a television set. Based on these results, we propose guidelines as well as specific features to inform the design of future “social television” prototypes.

The mad hatter's cocktail party: a social mobile audio space supporting multiple simultaneous conversations

This paper presents a mobile audio space intended for use by gelled social groups. In face-to-face interactions in such social groups, conversational floors change frequently, e.g., two participants split off to form a new conversational floor, a participant moves from one conversational floor to another, etc. To date, audio spaces have provided little support for such dynamic regroupings of participants, either requiring that the participants explicitly specify with whom they wish to talk or simply presenting all participants as though they are in a single floor. By contrast, the audio space described here monitors participant behavior to identify conversational floors as they emerge. The system dynamically modifies the audio delivered to each participant to enhance the salience of the participants with whom they are currently conversing. We report a user study of the system, focusing on conversation analytic results.

Taking the work out of workflow: mechanisms for document-centered collaboration

There are two aspects to technical support for collaborative activity; support for content work and support for coordination. The design of CSCW systems must typically address both of these, combining them in a collaborative application. This approach, however, suffers from a variety of well-known problems, not least the compatibility between collaborative and single-user applications, working styles and practices. In this paper, we describe an alternative approach that makes coordination and collaborative functionality an aspect of the collaborative artifact rather than a collaborative application. We present an infrastructure and a series of application examples to illustrate the idea of documentcentered collaboration, in which coordination and collaboration are separated from and independent of applications.

Sotto Voce: Facilitating Social Learning in a Historic House

This study examines visitors’ use of two different electronic guidebook prototypes, the second an iteration of the first, that were developed to support social interaction between companions as they tour a historic house. Three studies were conducted in which paired visitors’ social interactions were video- and audio-recorded for analysis. Using conversation analysis, the data from the use of prototype 1 and prototype 2 were compared. It was found that audio delivery methods were consequential to the ways in which visitors structurally organized their social activity. Further, the availability of structural opportunities for social interaction between visitors has implications for the ways in which the learning process occurs in museum settings.

A programming model for active documents

Traditionally, designers organize software system as active end-points (e.g. applications) linked by passive infrastructures (e.g. networks). Increasingly, however, networks and infrastructures are becoming active components that contribute directly to application behavior. Amongst the various problems that this presents is the question of how such active infrastructures should be programmed. We have been developing an active document management system called Placeless Documents. Its programming model is organized in terms of properties that actively contribute to the functionality and behavior of the documents to which they are attached. This paper discusses active properties and their use as a programming model for active infrastructures. We have found that active properties enable the creation of persistent, autonomous active entities in document systems, independent of specific repositories and applications, but present challenges for managing problems of composition.