With the arrival of 3G era, the rapid growth of intelligent mobile, and the fast development of mobile value-added service, the importance of service design is been highlighted. Besides the mobility, unrestricted space and time, safety and fashion, mobile also has rich applications such as SMS, games, payment, positioning and office, which are based on those features mentioned above. It has brought more convenience and flexible mobile service to users, brought opportunities to the enterprise, making the mobile value-added service become a booming industry. "Context" first appeared in the cognitive psychology and related fields, reflecting the current context and meanwhile using the knowledge related to the context, when expressing the knowledge. How to obtain the user's tacit knowledge, apply the design knowledge as well as articulate hidden factors, is meaningful to specifying design knowledge and making it match the user's knowledge, making smooth progress of mobile value-added service.Firstly, this paper explained the common methods at all stages in service design and defined context, tacit knowledge and explicit knowledge according to the related theories. Secondly, based on "context", it studied context analysis, dividing it into two parts—wide and narrow context analysis in mobile value-added service. And then it matched the user's cognitive knowledge to the designer's by studying how to obtain the user's tacit knowledge and apply the design knowledge, building the mapping model among designers, users, services and environment. Through building the design model which articulate the hidden factors of interface, it can articulate the interface of service system. At the same time, interface design research based on context mentions the service design and evaluation model based on context, and make the development process of service design more structured and scientific. After that, handheld mobile service is selected as the design support and "M-Coupon" mobile application is taken as an example. It did market research and user research through interviews and questionnaires, analyzed and knew about the user's needs, created personas and value-added service platform for M-Coupon. And defined the feature requirements, completed the interface prototype design. Finally, there is a prototype design testing based on the context, which completed user satisfaction and usability testing evaluation as well as expert assessments, verifying the articulation design theory of value-added service design based on context in handheld mobile devices. |