Computer Science researchers are investigating systems that exploit the benefits of collaborative computing technology in learning. There is, however little empirical evidence of the benefits and costs associated with different modes of computer support for collaborative learning. The authors describe an experiment that compares how well 51 children (aged ten and eleven) learnt to solve a small puzzle in three different collaborative learning conditions. Results showed no significant difference in learning outcomes among the three conditions, but revealed that girls solved the puzzle more slowly when collaborating.

Software architecture styles for developing multiuser applications are usually defined at a conceptual level, abstracting such low-level issues of distributed implementation as code replication, caching strategies and concurrency control policies. Ultimately, such conceptual architectures must be cast into code. The iterative design inherent in interactive systems implies that significant evolution will take place at the conceptual level. Equally, however, evolution occurs at the implementation level in order to tune performance. This paper introduces Dragonfly, a software architecture style that maintains a tight, bidirectional link between conceptual and implementation software architectures, allowing evolution to be performed at either level. Dragonfly has been implemented in the Java-based TeleComputing Developer (TCD) toolkit.

User centered design requires the creation of numerous design artifacts such as task hierarchy, task-oriented specification, user interface design, architecture design and code. It is increasingly accepted that such artifacts cannot be created in isolation, but instead incrementally coevolve, where information obtained from the development of one artifact contributes to the development of the others. In user interface development, these artifacts are typically developed by different people with different backgrounds, hindering the communication necessary for coevolution. This paper demonstrates how different design artifacts can be linked, exposing their common elements. Such links can be developed despite the differing points of view and differing levels of detail of the design artifacts. This paper describes Vista, a prototype tool for examining the links between design artifacts, and demonstrates how making these links explicit supports coevolutionary design.