Posters: Supporting Design: Paper or Interactive? A Study of Prototyping Techniques for Ubiquitous Computing Environments

We studied the effects of varying the fidelity and automation levels of a Ubicomp application prototype. Our results show that the interactive prototype captured the same usability issues that the paper prototype studies did and more. We found that paper prototyping is insufficient for supporting unique Ubicomp requirements, such as scalability, but a prototype with higher fidelity and automation levels can enhance the quality of interaction data available for evaluation. Keywords Ubiquitous Computing, Lo-fi Prototyping, Wizard of Oz. INTRODUCTION Ubiquitous Computing promises to augment and transform daily tasks by enabling natural interaction with everyday environments. However, there has been little research on the design and evaluation process for Ubicomp applications [1]. Although prototyping has been used with great success in obtaining usability data during the design of traditional UIs [2,3], its use in Ubicomp has not been thoroughly investigated. We wanted to identify the appropriate level of prototyping fidelity (look and feel) and automation (amount of human intervention) to successfully design Ubicomp applications. To do this, we designed and evaluated Kitchen-Net, a simple Ubicomp application for locating items in industrialsized kitchens. We evaluated two prototypes of differing fidelity and automation level. Our results showed that prototype fidelity was an important factor in eliciting quality feedback, and automation level was an important factor in uncovering major usability issues. THE KITCHEN-NET SYSTEM We ran formative studies at two student cooperatives, looking for tasks that a Ubicomp system could augment. We noticed that cooks had trouble finding the items they needed, given the size of their industrial kitchens. To assist them in locating items, we designed Kitchen-Net. Kitchen-Net supports the task of working in an industrial kitchen by responding to spoken queries for items (e.g., “where is…” or “show me…”). Kitchen-Net uses a set of screens placed around the kitchen. The screen nearest the user shows directions to his or her requested item. The level of detail of the directions is proportional to the user’s proximity to the item. To study the effects of varying fidelity and automation levels on usability, we created both a paper and interactive prototype of Kitchen-Net. We employed a Wizard of Oz strategy to simulate a voice-recognition system and a sensor network system for tracking item and user locations. The wizard enters contextual events (e.g., speech or user movement) in real-time to an event logger that we developed. Paper Prototype We used paper sketches and Post-It notes to represent Kitchen-Net screens (see Figure 1). There was minimal automation involved in running this prototype. One researcher played the wizard and the other played the “computer.” The “computer” manually updated screens in response to spoken queries and user movement events. We implemented the paper prototype in a day and incorporated major implementation changes very quickly. Interactive Prototype We replaced the paper “screens” with Vadem Clio Handheld PCs (see Figures 2a and 2b). This prototype automatically responded to events logged by the wizard, removing the need for the human “computer.” We needed two weeks to implement this prototype and roughly a day to incorporate each major implementation change. EXPERIMENT DESIGN Two sets of studies were conducted with both prototypes on twenty college students. All were cooks for Cloyne Court, a co-op housing 150 people. Eleven females and nine males were all between the ages of 18-25. Their experience cooking meals for the house varied. Participants were asked to consider making spoken queries to Kitchen-Net when looking for any item. The studies ended with a short questionnaire. Copyright is held by the author/owner(s). CHI 2003, April 5–10, 2003, Ft. Lauderdale, Florida, USA. ACM 1-58113-630-7/03/0004. Interactive & Student Posters: Supporting Design CHI 2003: NEW HORIZONS Posters: Supporting Design Copyright is held by the author/owner(s). CHI 2003, April 5-10, 2003, Ft. Lauderdale, Florida, USA. ACM 1-58113-637-4/03/0004