We introduce a new usability walkthrough method called Collaborative Critique (CC), which is inspired by the human-computer collaboration paradigm of system-user interaction. This method applies a "collaboration lens" to assessing the system's behavior and its impact on the user's efforts in the context of the task being performed. We present findings from a laboratory evaluation of the CC method with usability practitioners, in which the results of the CC walkthrough were compared to a benchmark set of problems collected via user testing with two experimental Enterprise Resource Planning (ERP) system tasks. The development of this new usability evaluation method was driven by the need for an approach that assesses the adequacy of the system's support for reducing the user's cognitive and physical effort in the context of the interaction.

Modern museums provide visitors with mobile, context-aware information and guidance systems. Unfortunately, these systems often suffer from several technological drawbacks: expensive infrastructure, complex maintenance and content modification, difficult to learn user interfaces, manual location specification requirements, etc. Visitors have to rent, learn, carry and return yet another mobile device. On the other hand, most modern nomadics already own high-performance mobile devices: smart-phones. But acceptance to install museum software on a personal device is rather limited. In this paper, a novel mobile, context-aware museum information system is introduced that runs on the visitors' mobile phones without any prior installation. We outline the technical principles of the underlying Medient infrastructure and present HolstenTour as an example service instantiation for the famous Museum Holstentor in Luebeck, Germany.