Tools Supporting Co-located Collaboration

Stewart et al. [70] introduced Single Display Groupware (SDG) as a model for supporting co-located face-to-face collaboration. SDG typically contains a single display with multiple input devices for simultaneous use. They argued that the being able to work more effectively by working in parallel is one of the benefits of using SDG in the creative domain including brainstorming and other creative, expressive tasks. However, working in parallel may also be a disadvantage if there are conflicts in users’ intentions. One user’s decision could negatively affect others. Working in parallel with multiple input devices may reduce collaboration because users are able to work on their own tasks without communication with collaborators.

Various studies had used SDG on many different collaborative sensemaking tasks. Shen et al. [71] developed Personal Digital Historian (PDH) system for multiple users to share and build the digital group histories on an interactive tabletop. Users can explore, annotate, group and query photos, videos, and text documents in dif- ferent layouts of these digital materials based on person, event, location, and time. Users can also rotation the hole interface and resize individual object. PDH fa- cilitates conversation and storytelling among users. However, it used the digital materials collected prior to the tasks. Users could not actively add information to the system during the tasks.

ing [41]. Many studies investigated collaborative search, where multiple users work together to fulfill a shared information need [72]. For example, Morris et al. [73] developed WeSearch to support collaborative search and sensemaking on a tabletop touch display. Each participant takes one side of the display with her own browser window and software keyboard as input device. One unique feature is that users can make clips such as related keywords, web search results, images, and news article summaries from the web pages. Such features facilitate collaboration among users. Although the result of the study showed that clips did not directly support division of labor to increase the efficiency, they did help the sensemaking process and reduce the clutter. However, personal spaces on a single tabletop caused clutter issues and the software keyboards on the tabletop provided subpar text-entry experiences.

Other studies incorporate personal devices with the shared single display, ex- tending the SDG model. Amershi et al. [55] developed CoSearch that allows users to conduct collaborative search using their mobile phones to control the shared- computer through Bluetooth connection. Uses summit their own search requests from the mobile phones and the requests are queued on the shared-computer. The shared-computer transfers the results or the web page back to the mobile phones for personal use. CoSearch increases the efficiency of the collaborative search than using single shared-computer by enabling distributed control and division of labor.

With the advancement of the mobile technologies, smartphones and tablets be- come increasingly powerful. The users can perform more tasks on the personal devices. Seifert et al. [29] designed MobiSurf that enabled users to conduct web searching in a co-located collaboration way through integrated mobile devices and interactive surfaces. Users can switch freely between devices during the tasks since both mobile devices and shared surface support simple web browsing. They can also transfer the URLs of web pages between mobile devices and the shared surface

using PhoneTouch [61]. In the tasks of trip planning and gift shopping, MobiSurf enhanced sharing, communication and awareness between collaborators than using multiple laptops and sharing through instant messages.

Multiple personal devices connected to a shared surface have supported use cases other than collaborative search. Sugimoto et al. [64] developed Caretta, a system integrating a shared multiple input sensing board and PDA devices to support col- laboration in urban planning tasks. Users can switch seamlessly between working on their own ideas on the personal spaces on PDAs and cooperating with others on the shared surface. In Caretta, the personal space can either mirror the shared space or show a portion of it. Providing a personal space for a user is beneficial since a user can experiment and simulate the result on her PDA before sharing it to the group without interfering her collaborators.

Wallace et al. [74] studied the co-located collaborative sensemaking process using different combinations of shared tabletop and tablet devices. In one condition, par- ticipants each had a tablet containing unique information that they could share to the tabletop to obtain best outcome through group discussion. In the sensemaking task, the participants individually explore and examine information on their tablets, compare shared information on the tabletop, arrange the information in the forms of tableaux in order to describe the result. Using shared tabletop with tablets sig- nificantly increases insights/depth of the discussion than using tablets alone. Users shared more information to the tabletop from the tablets than using the tabletop only.

We present a unique embodied cross-surface interaction technique between mobile devices and a collaborative surface that support group information-based ideation with multiple displays. Co-located users collect rich information on the mobile de- vices and share them to the collaborative surface. They also collaborate on the col-

laborative surface to manipulate the shared information to facilitate their ideation tasks.