Abstract. This paper draws on the design process, implementation and early evaluation results of an urban screens network to highlight the tensions that emerge at the boundary between the technical and social aspects of design. While public interactive screens in urban spaces are widely researched, the newly emerging networks of such screens present fresh challenges. Researchers wishing to be led by a diverse user community may find that the priorities of some users, directly oppose the wishes of others. Previous literature suggests such tensions can be handled by 'goal balancing', where all requirements are reduced down to one set of essential, implementable attributes. Contrasting this, this paper's contribution is 'Tension Space Analysis', which broadens and extends existing work on Design Tensions. It includes new domains, new representational methods and offers a view on how to best reflect conflicting community requirements in some aspects or features of the design.

Abstract. Large public displays are becoming a ubiquitous resource in the urban environment. Interconnected over the Internet these hitherto isolated "ad displays" could become a novel and powerful communication medium -networked public displays. One example for such a novel type of communication is their use as community tools. Scattered across the urban landscape and equipped with additional sensors, such as cameras, they provide the opportunity for local community members to take images of themselves and leave their "mark" in the setting, e.g., on their way to school, work, or meeting with friends. In order to understand the potential of posting situated snapshots on networked public displays in the context of place-based communities we designed and developed the Moment Machine -a networked public display application that allows one-click photo capture. In this paper we report on identified opportunities and challenges emerging from 6 user trials in the wild at 2 locations.

Overlaying a building with images from the past can be an engaging way to explore a historic site. However, little is known about what type of content functions well when using augmented reality (AR) in outdoor contexts. This research investigates how different types of AR content-such as text or image-can affect the flow experience as well as other cognitive, affective and behavioral responses. We ran an experimental study with 85 participants at a university campus, where three groups used different apps-AR app with overlaid textual information, AR app with overlaid both textual information and images and an app with audio guide-to explore the area's historic and cultural background. The results show that overlaying images in addition to the text was clearly the most successful way of attracting attention and providing stronger flow in comparison to the apps that overlaid only text or delivered audio. However, we also discovered that users occasionally interpreted the overlaid imagery to be cues for something else other than what they were designed to represent. Finally, we discuss how AR content can enlarge otherwise invisible details, depict historic elements and unveil interiors of buildings.

Urban screens are becoming a common element of our city landscape. As such they offer new ways of connecting people that occupy public space, e.g., by taking situated snapshots through a display-attached camera. In this paper we present a first longitudinal case study of 12 weeks of such an application -Moment Machine -deployed "in the wild" on an urban screen facing the street. We report findings from 1189 photos taken, 13 interviews, and 3 weeks of observations that show engagement stimulated by situated snapshots within a place-based community where the screen is located. We also analyze interaction log files to describe how often users interacted, what type of interactions they had and how long they lasted, and overall engagement on a weekly basis and throughout the week. Based on our experience, we provide three take-away snippets for designers of similar urban screen experiences.

Abstract.Highly diverse settings such as London (with people from ~179 countries speaking ~300 languages) are unique in that ethnic or socio-cultural backgrounds are no longer sufficient to generate a sense of place, belonging and community. Instead, residents actively perform place building activities on an ongoing basis, which we believe is of great importance when deploying interactive situated technologies in public spaces. This paper investigates community and place building within a complex multicultural context. We approached this using ethnography, complemented with workshops in the wild. By studying the relationships arising between different segments of the community and two networked screen nodes, we examine the place building activities of residents, and how screen nodes are incorporated into them. Our research suggests that urban screens will be framed (and eventually used) as part of this continuing process of social, spatial and cultural construction. This highlights the importance of enabling socially meaningful relations between the people mediated by these technologies.