Evaluating the Interactivity of Ubiquitous Services: an Integrated Metric Based on Ucd (User-centered Design) Principles

Ubiquitous computing environments attempt to build up not only the existing method that supports services on requests but also the service that will provide optimum services by perceiving the behaviors and intentions of users (conceptual approach u-Service). The complexity of the contents provided to users through u-Service is suggested as the concept of interactivity which is the expansion of the concept of usability. The evaluation model for u-Service interactivity was approached from usability, inter-personal services, and psychometric theory. This study suggested a quantitative metric for user testing and affective modeling performed after classifying the interactivity characteristics (contextualization, ubiquity, user experience, service capability). As a validation study, relationships among interactivity metric and characteristic of u-Service were investigated using quantification I-type analysis and logistic regression. The result of the case study showed that proposing u-Service interactivity metric to evaluate overall interaction capability of u-Service is a valid and effective approach in user-centered u-Service assessment.