ABSTRACT

As communications systems increasingly gather and propagate information about people’s reachability or “presence”, users need better tools to minimize undesired interruptions while allowing desired ones. We review the salient elements of presence and availability that people use when initiating face-to-face communication. We discuss problems with current strategies for managing one’s availability in telecommunication media. We describe a prototype system called Lilsys which passively collects availability cues gathered from users ’ actions and environment using ambient sensors and provides machine inferencing of unavailability. We discuss observations and design implications from deploying Lilsys. Categories and Subject Descriptor

Exploring Web Browser History Comparisons

This work explores how comparing web navigation histories between two people and presenting the results to them might allow them to gain insight about each other. We developed a prototype that presents web matches sorted according to frequency, recency, and web site. Interviews with users of the prototype suggest that common interests and preferences can be inferred from these comparisons

Internet Based Real-Time Multiuser Simulation: Ppong!

There is a growing demand for real-time collaborative applications through the World Wide Web. New techniques are required for real-time applications to perform well in the face of changing network conditions that often include long delays. We present some of the key issues for implementors of real-time web-based applications, including choices on centralized versus distributed control, two versus multiuser considerations, synchronous versus asynchronous message protocols, and simulation divergence. We present an implementation for a web-based version of the classic Pong game, called Ppong!. Ppong! was selected for implementation since it strips to its essentials many components of real-time collaborative simulation. A key feature of Ppong! is implementation of a heuristic for "retarding" a user's view of the simulation to accommodate network delays

Activity Rhythm Detection and Modeling

We present an algorithm for detecting and modeling rhythmic temporal patterns from the record of an individual's computer activity, or online "presence." The model is both predictive and descriptive of temporal features and is constructed with minimal a priori knowledge

Flexible Collaboration Transparency

This paper presents two distinct contributions: First, we present a critique of collaboration transparency as it is currently implemented in contrast to collaboration-aware implementations. We find conventional collaboration-transparency systems lacking in terms of efficient use of network resources and support for key groupware principles: concurrent work, relaxed WYSIWIS, and group awareness. Second, we examine the causes of these deficiencies, and then present an alternative implementation approach based on an object-oriented replicated architecture where selected single-user interface objects are dynamically replaced by multi-user extensions. The replacement is transparent to the single-user application and its developer. As an instance of this approach, we described its incorporation into a Java-based collaboration-transparency system, called JAMM