Chapter 6: User Interfaces for Mobile Media 247 requirements to make the functionality and technology accessible. A mobile device is often a single unit, therefore, different kinds of form factors and interaction device confi gurations will have an impact on industrial and hardware design, etc. Regardless of methodology, the UI design process consists of four distinguished phases: • analyzing users, tasks, and operations • specifying UI structure • defi ning UI components, and • layout and visual design. In the fi rst phase, the target users and their characteristics (such as background, experience, and language) are defi ned, and the tasks that the user should be able to perform with the application are analyzed. The designer must understand why the application (for example, a music player) is being designed and what are the most important tasks (such as playing back a playlist, creating a playlist, or browsing the music library) that the user wishes to accomplish. Often the tasks are presented by use cases or scenarios, which are spoken language descriptions of ways to use the system, related sequences of opera- tions, and the operating environment. Based on the task analysis, the designer can start to identify the operations that are required to perform the tasks. Operations are ele- mentary procedures consisting of a series of actions that the user per- forms. Actions are the smallest activities that the user can perform with the actual user interface (for instance, pushing a button, or scrolling a list). Making a playlist requires the user to create a new playlist, to select desired songs, and to save the playlist. After the operation analysis is complete, the designer summarizes all the defi ned operations as a list to identify what unique operations the tasks share. This way the designer can keep the design simple and consistent between the tasks. Before moving on to the next phase, the designer should be aware of the platform and other technical aspects, such as technical con- straints, requirements, and possibilities, which will infl uence the design. For example: What kind of form factor is used? What is the display size and resolution? What kinds of input devices are available for the interaction? Furthermore, the platform may provide an UI guideline (Series60. com 2005; UIQ Technology 2002) for the designer that describes the