Being guided from one place to another is a pervasive social practice that connects deeply with socially aware robot navigation. We examine how robots come to feature within the organisation of these established and well-worn leading and following practices, practices which are assembled 'in place' by the efforts of individuals and groups that are using robot guides. We deployed mobile robots in a museum context to provide additional information for visitors around multiple sequential exhibits. Our ethnomethodological video-based analysis of interaction centres on how the social organisation of being guided was practically managed by visitors: in initiation of following, doing following, and finding a place to stop. Our study shows how following and being led is more than just a mechanical activity, and describe the implications for socially aware robot navigation in addressing novel technical challenges that a shift in understanding following-leading phenomena presents.

If robots are to be deployed in public places, we need to understand what factors their design should consider. Informed by sociological studies of urban settings, particularly the work of William H. Whyte and the Street Life Project, we describe four characteristics of public places that affect and are affected by robot design: (1) localism-how robot design aligns with the identity, culture, and character of the place(s) they reside within; (2) environments-the physical characteristics of the environment in which public robots operate; (3) activities- consideration for the various daily, occasional, and situational activities that are tied to place(s) robots inhabit; and (4) sociability- how people collectively and individually relate to, interact with, and make sense of robots deployed in public places. Throughout, we illustrate these characteristics with examples drawn from empirical studies of public robots. We discuss how these key characteristics of public places can inform HRI design.

As we see robots being deployed into new places in everyday life, questions arise about what 'human-robot collaboration' (HRC) might look like there. At the same time, HRC researchers are looking to CSCW for better conceptualisations of 'collaboration', and recent work has called for more CSCW-oriented studies of HRC to support this. We address this via an ethnomethodological study of encounters between pedestrians and food delivery robots on public streets. Our analysis--using video recorded fragments of what happens on the streets--demonstrates how passers-by continuously manage walking trajectories in ways that account for robot actions; specifically we articulate how people accomplish practices of following and overtaking robots, passing by and crossing paths with them. We then show that the picture of human-robot collaboration is drawn with distinct asymmetries of action and intelligibility, where humans contribute considerable work to get something that looks like 'collaboration' achieved. This raises fundamental questions for how we talk about concepts of collaboration in HRC from a CSCW perspective, and how such notions can and should be applied to activities which include robots.

Robots deployed in public settings enter spaces that humans live and work in. Studies of HRI in public tend to prioritise direct and deliberate interactions. Yet this misses the most common form of response to robots, which ranges from subtle fleeting interactions to virtually ignoring them. Taking an ethnomethodological approach building on video recordings, we show how robots become embedded in urban spaces both from a perspective of the social assembly of the physical environment (the streetscape) and the socially organised nature of everyday street life. We show how such robots are effectively 'granted passage' through these spaces as a result of the practical work of the streets' human inhabitants. We detail the contingent nature of the streetscape, drawing attention to its various members and the accommodation work they are doing. We demonstrate the importance of studying robots during their whole deployment, and approaches that focus on members' interactional work.

Abstract Control rooms have long been a key domain of investigation in HCI and CSCW as sites for understanding distributed work and fragmented settings, as well as the role and design of digital technologies in that work. Although research has tended to focus mainly on ‘command and control’ configurations, such as rail transport, ambulance dispatch, air traffic and CCTV rooms, centres of coordination shaped by artistic and performative concerns have much to contribute. Our study examines how a professional team of artists and volunteers stage manage and direct the performance of a mixed reality game from a central control room, with remote runners performing live video streaming from the streets nearby to online players. We focus on the work undertaken by team members to bring this about, exploring three key elements that enable it. First, we detail how team members oriented to the work as an artistic performance produced for an audience, how they produced compelling, varied content for online players, and how the quality of the work was ongoingly assessed. Second, we unpack the organisational hierarchy in the control room’s division of labour, and how this was designed to manage the challenges of restricted informational visibility there. Third, we explore the interactional accomplishment of the performance by looking at the role of radio announcements from the event’s director to orchestrate how the performance developed over time. Announcements were used to resolve trouble and provide instructions for avoiding future performative problems; but more centrally, to give artistic direction to runners in order to shape the performance itself. To close we discuss how this study of a performance impacts CSCW’s understandings of control room work, how the problem of ‘diffuse’ tasks like artistic work is co-ordinated, and how orientations towards quality as an artistic concern is manifest in / as control room practices. We also reflect on hierarchical and horizontal control room arrangements, and the role of video as both collaborative resource and product. Graphical abstract

Mobile Robotic Telepresence (MRP) systems afford remote communication with an embodied physicality and autonomous mobility, which is thought to be useful for creating a sense of presence in hybrid activities. In this paper, drawing on phenomenology, we interviewed seven long term users of MRP to understand the lived experience of participating in hybrid spaces through a telepresence robot. The users' accounts show how the capabilities of the robot impact interactions, and how telepresence differs from in-person presence. Whilst not feeling as if they were really there, users felt present when they were being able to participate in local action and be treated as present. They also report standing out and being subject to behaviour amounting to 'othering'. We argue that these experiences point to a need for future work on telepresence to focus on giving remote users the means to exercise autonomy in ways that enable them to participate --- to be 'in on the action' --- rather than in ways that simply simulate being in-person.

IoT solutions is their long-term socio-technical infrastructural nature, and therefore long-term installation and maintenance needs. This adds complexity to both the practice of digital plumbing and to the work of design that supports it. In this paper we study a commercial company producing and installing IoT alarm systems. We examine video recordings that capture how a digital plumbing representative and software development team members make changes to both the installation process and supporting technology. Our data enables us to critically reflect on concepts of infrastructuring, and uncover the ways in which the team methodically foreground hidden elements of the infrastructure to address a point of failure experienced during field trials of a new version of their product. The contributions from this paper are twofold. Firstly, our findings build on previous examples of infrastructuring in practice by demonstrating the use of notions of elemental states to support design reasoning through the continual foregrounding and assessment of tensions identified as key factors at the point of failure. Secondly, we build on current notions of digital plumbing work. We argue that additional responsibilities of 'reporting failure' and 'facilitation of change' are part of the professional digital plumbing role and that commercial teams should support these additional responsibilities through collaborative troubleshooting and design sessions alongside solid communication channels with related stakeholders within the product team.

Facial recognition technology (FRT) has become a significant topic in CSCW owing to widespread adoption and related criticisms: the use of FRT is often considered an assault on privacy or a kind of neo-phrenology. This discussion has revolved around uses of FRT for identification, which are often non-voluntary, in particular for surveillance wherein people are (by and large) unwittingly recognized by FRT systems. At the same time, we have also seen a rise of forms of FRT for verification (e.g., passport control or Apple's Face ID), which typically are overt and interactive. In this paper we study an interactive FRT system used for guest check-in at a hotel in China. We show how guests and bystanders engage in 'self-disciplining work' by controlling their facial (and bodily) comportment both to get recognized and at times to avoid recognition. From our analysis we discuss the role of preparatory and remedial work, as well as dehumanization, and the importance of CSCW paying closer attention to the significance of interactional compliance for people using and bystanding facial recognition technologies.

Bipolar Disorder (BD) is a complex, cyclical and chronic mental illness where self-tracking is central to self-management. Mobile technology is often leveraged to support this. Limited research has investigated the everyday practices of self-tracking for BD, and it is unclear how the normative ontology that is seen in existing self-tracking technology discourses (e.g. the Quantified Self movement) is applicable to the domain of mental health. Combining principles of Patient and Public Involvement (PPI)—a staple research design principle in mental healthcare—with design and HCI-oriented research approaches, we conducted interviews and workshops with people with lived experience of BD to explore reasons and methods for self-tracking, and challenges and opportunities for technology. Our results describe recommendations for the design of self-tracking mental health technology. We also reflect upon the complex role of researchers working at the intersection of emerging mental health technologies, the principles of PPI, and HCI research.

Mobile Robotic Telepresence (MRP) systems are remotely controlled, mobile videoconferencing devices that allow the remote user to move independently and have a physical presence in the environment. This paper presents a longitudinal study of MRP use in the home, where the first author used an MRP to connect with family, her partner, and friends over a six-month period. Taking an ethnomethodological approach, we present video recorded fragments to explore the phenomenon of ‘visiting’ where MRP users drop into the home for a period of time. We unpack the more ‘procedural’ elements—arriving and departing—alongside ways of ‘dwelling’ together during a visit, and the qualities of mobility, autonomous presence and spontaneity that emerge.

Recent HCI research has sought to develop guidelines—‘heuristics’, ‘best practices’, ‘principles’ and so on—for voice user interfaces (VUI) to aid both practitioners and researchers in improving the quality of VUI-based design. However, limited research is available on how such design knowledge is conceptualised and used by industry practitioners. We present a small interview-based study conducted with 9 experienced VUI industry practitioners. Their concerns range from terminological challenges associated with VUI design knowledge, the role of codifications of such knowledge like design guidelines alongside their practical design work, through to their views on the value of ‘harmonisation’ of VUI design knowledge. Given the complex—albeit preliminary—picture that emerges, we argue for HCI's deeper consideration of how design knowledge meshes with the contingencies of practice, so that VUI design knowledge—such as design guidelines developed in HCI—delivers the most potential value for industry practice.

Technology “demos” have become a staple in technology design practice, especially for showcasing prototypes or systems. However, demonstrations are also commonplace and multifaceted phenomena in everyday life, and thus have found their way into empirical research of technology use. In spite of their presence in HCI, their methodical character as a research tool has so far received little attention in our community. We analysed 102 video-recorded demonstrations performed by visually impaired people, captured in the context of a larger ethnographic study investigating their technology use. In doing so, we exhibit core features of demonstrational work and discuss the relevance of the meta-activities occurring around and within demonstrations. We reflect on their value as an approach to doing HCI research on assistive technologies (AT), for enabling shared understanding and letting us identify opportunities for design. Lastly, we discuss their implications as a research instrument for accessibility and HCI research more broadly.

Mobile video calling technologies have become a critical link to connect distributed families. However, these technologies have been principally designed for video calling between two parties, whereas family video calls involve young children often comprise three parties, namely a co-present adult (a parent or grandparent) helping with the interaction between the child and another remote adult. We examine how manipulation of phone cameras and management of co-present children is used to stage parent-child interactions. We present results from a video-ethnographic study based on 40 video recordings of video calls between 'left-behind' children and their migrant parents in China. Our analysis reveals a key practice of 'facilitation work', performed by grandparents, as a crucial feature of three-party calls. Facilitation work offers a new concept for HCI's broader conceptualisation of mobile video calling, suggesting revisions that design might take into consideration for triadic interactions in general.

More than a billion people in the world live with some form of visual impairment, and a wide variety of technologies are now routinely used by them in the course of 'getting on' in everyday life. However, little is known about the ways in which assistive and non-assistive technologies are brought to bear on material practices. We present findings from a four-month ethnographic study facilitated by a local branch of a UK charity that supports people with visual impairments. Our study explores mainstream and assistive technology use within their everyday lives. We identify three main sites for technology use: social relations and communication practices, textual reading practices, and mobility practices. Via an ethnographic approach we contribute to understanding how people accomplish such practices, and in doing so, uncover the practical competencies that enable people with visual impairments to conduct their everyday activities. Thus we investigate how disability can be thought of in terms of competencies, arguing that understanding of competencies can enrich the design of technologies that fit the needs of people with visual impairments.

Via audiovisual communications and a controllable physical embodiment, Mobile Robotic telePresence (MRP) systems aim to support enhanced collaboration between remote and local members of a given setting. But MRP systems also put the remote user in positions where they frequently rely on the help of local partners. Getting or 'recruiting' such help can be done with various verbal and embodied actions ranging in explicitness. In this paper, we look at how such recruitment occurs in video data drawn from an experiment where pairs of participants (one local, one remote) performed a timed searching task. We find a prevalence of implicit recruitment methods and outline obstacles to effective recruitment that emerge due to communicative asymmetries that are built into MRP design. In a future where remote work becomes widespread, assistance through remote work technology like MRPs needs close examination at a fundamental interactional level, taking into account how communicative asymmetries are at play in everyday use of such technologies.

The Wizard of Oz method is an increasingly common practice in HCI and CSCW studies as part of iterative design processes for interactive systems. Instead of designing a fully-fledged system, the 'technical work' of key system components is completed by human operators yet presented to study participants as if computed by a machine. However, little is known about how Wizard of Oz studies are interactionally and collaboratively achieved in situ by researchers and participants. By adopting an ethnomethodological perspective, we analyse our use of the method in studies with a voice-controlled vacuum robot and two researchers present. We present data that reveals how such studies are organised and presented to participants and unpack the coordinated orchestration work that unfolds 'behind the scenes' to complete the study. We examine how the researchers attend to participant requests and technical breakdowns, and discuss the performative, collaborative, and methodological nature of their work. We conclude by offering insights from our application of the approach to others in the HCI and CSCW communities for using the method.

The gap between research and design practice has long been a concern for the HCI community. In this article, we explore how different translations of HCI knowledge might bridge this gap. A literature review characterizes the gap as having two key dimensions—one between general theory and particular artefacts and a second between academic HCI research and professional UX design practice. We report on a 5-year engagement between HCI researchers and a major media company to explore how a particular piece of HCI research, the trajectories conceptual framework , might be translated for and with UX practitioners. We present various translations of this framework and fit them into the gap we previously identified. This leads us to refine the idea of translations , suggesting that they may be led by researchers, by practitioners or co-produced by both as boundary objects . We consider the benefits of each approach.

Usability testing has long been a core interest of HCI research and forms a key element of industry practice. Yet our knowledge of it harbours striking absences. There are few, if any detailed accounts of the contingent, material ways in which usability testing is actually practiced . Further, it is rare that industry practitioners’ testing work is treated as indigenous and particular (instead subordinated as a ‘compromised’ version). To service these problems, this article presents an ethnomethodological study of usability testing practices in a design consultancy. It unpacks how findings are produced in and as the work of observers analysing the test as it unfolds between moderators taking participants through relevant tasks. The study nuances conventional views of usability findings as straightforwardly ‘there to be found’ or ‘read off’ by competent evaluators. It explores how evaluators/observers collaboratively work to locate relevant troubles in the test's unfolding. However, in the course of doing this work, potential candidate troubles may also routinely be dissipated and effectively ‘ignored’ in one way or another. The implications of the study suggest refinements to current understandings of usability evaluations, and affirm the value to HCI in studying industry practitioners more deeply.

Voice User Interfaces (VUIs) are becoming ubiquitously available, being embedded both into everyday mobility via smartphones, and into the life of the home via 'assistant' devices. Yet, exactly how users of such devices practically thread that use into their everyday social interactions remains underexplored. By collecting and studying audio data from month-long deployments of the Amazon Echo in participants' homes-informed by ethnomethodology and conversation analysis-our study documents the methodical practices of VUI users, and how that use is accomplished in the complex social life of the home. Data we present shows how the device is made accountable to and embedded into conversational settings like family dinners where various simultaneous activities are being achieved. We discuss how the VUI is finely coordinated with the sequential organisation of talk. Finally, we locate implications for the accountability of VUI interaction, request and response design, and raise conceptual challenges to the notion of designing 'conversational' interfaces.

Despite the rise of social media and online communication, face-to-face interaction retains its prominence in human life. Being face to face with others is “the most human thing that we do” (Turkle...

In this commentary I discuss Noam Tractinsky’s article “The Usability Construct: A Dead End?” (2017), which provides a thoughtful meditation on the notion of “usability.” Usability is a troublesome...

We explore spectating on video game play as an interactional and participatory activity. Drawing on a corpus of video recordings capturing 'naturally occurring' Kinect gaming within home settings, we detail how the analytic 'work' of spectating is interactionally accomplished as a matter of collaborative action with players and engagement in the game. We examine: spectators supporting players with continuous 'scaffolding'; spectators critiquing player technique during and between moments of play; spectators recognising and complimenting competent player conduct; and spectators reflecting on prior play to build instructions for the player. From this we draw out a number of points that shift the conversation in HCI about 'the spectator' towards understanding and designing for spectating as an interactional activity; that is, sequentially ordered and temporally coordinated. We also discuss bodily conduct and the particular ways of 'seeing' involved in spectating, and conclude with remarks on conceptual and design implications for HCI.

We present a case study of how Human-Computer Interaction (HCI) theory is reused within the field. We analyze the HCI literature in order to reveal the impact of one particular theory, the trajectories framework that has been cited as an example of both contemporary HCI theory and a strong concept that sits between theory and design practice. Our analysis of 60 papers that seriously engaged with trajectories reveals the purposes that the framework served and which parts of it they used. We compare our findings to the originally stated goals of trajectories and to subsequent claims of its status as both theory and strong concept. The results shed new light on what we mean by theory in HCI, including its relationship to practice and to other disciplines.

Over the last decade, there has been an explosion of work around social media within CSCW. A range of perspectives have been applied to the use of social media, which we characterise as aggregate, actor-focussed or a combination. We outline the opportunities for a perspective informed by ethnomethodology and conversation analysis (EMCA)-an orientation that has been influential within CSCW, yet has only rarely been applied to social media use. EMCA approaches can complement existing perspectives through articulating how social media is embedded in the everyday lives of its users and how sequentiality of social media use organises this embeddedness. We draw on a corpus of screen and ambient audio recordings of mobile device use to show how EMCA research is generative for understanding social media through concepts such as adjacency pairs, sequential context, turn allocation / speaker selection, and repair.

Command and control environments ranging from transport control rooms to disaster response have long been of interest to HCI and CSCW as rich sites of interactive technology use embedded in work practice. Drawing on our engagement with disaster response teams, including ethnography of their training work, we unpack the ways in which situational uncertainty is managed while a shared operational 'picture' is constituted through various practices around tabletop work. Our analysis reveals how this picture is collaboratively assembled as a socially shared object and displayed by drawing on digital and physical resources. Accordingly, we provide a range of principles implicated by our study that guide the design of systems augmenting and enriching disaster response work practices. In turn, we propose the Augmented Bird Table to illustrate how our principles can be implemented to support tabletop work.

We present a study of a mixed reality game called 'I'd Hide You' that involves live video streaming from the city streets. We chart the significant challenges facing performers on the streets who must simultaneously engage in the game, stream compelling video footage featuring themselves, and interact with a remote online audience. We reveal how these street performers manage four key tensions: between their body and camera; between the demands of online audiences and what takes place on-the-street; between what appears 'frontstage' on camera versus what happens 'backstage'; and balancing being a player of the game with being a performer. By reflecting on how they achieve this, we are able to draw out wider lessons for future interfaces aimed at supporting people broadcasting video of themselves to online audiences while engaged in games, sports and other demanding real-world activities.

Many of our everyday social interactions involve mobile devices. Yet, these tend to only provide good support for distributed social interactions. Although much HCI and CSCW research has explored how we might support collocated, face-to-face situations using mobile devices, much of this work exists as isolated exemplars of technical systems or interaction designs. This paper draws on a range of such exemplars to develop a practical design framework intended for guiding the design of new mobile experiences for collocated interaction as well as analysing existing ones. Our framework provides four relational perspectives for designing the complex interplay between: the social situation in which it takes place; the technology used and the mechanics inscribed; the physical environment; and the temporal elements of design. Moreover, each perspective features some core properties, which are highly relevant when designing these systems. As part of presenting the framework we also explain the process of its construction along with practical advice on how to read and apply it.

We present a study of how filmmakers collected and visualized physiological data—“biodata”—to construct a series of short promotional films depicting people undergoing “thrilling” experiences. Drawing on ethnographic studies of two major advertising campaigns, we highlight key concerns for integrating sensors and sensor data into film production. Our findings address the perceived benefits of using biodata within narratives; the nature of different on-screen representations of biodata; and the challenges presented when integrating biodata into production processes. Drawing on this, we reconsider the nature of information visualization in the filmmaking context. Further implications from our case studies provide recommendations for human--computer interaction (HCI) collaborations with filmmaking and broadcast industries, focusing both on the practical matters of fitting sensor technologies into and handling data within production workflows, as well as discussing the broader implications for managing the veracity of that data within professional media production.

Cultural institutions, such as museums, often curate politically and ethically sensitive materials. Increasingly, Internet-enabled, digital technology intersects with these curatorial practices offering new opportunities for public and scholarly engagement. We report on a case study of human rights media archiving at a genocide memorial centre in Rwanda, motivated by our interests in ICT support to memorialisation practices. Through an analysis of our discussions with staff about their work, we report on how accounts of the Rwandan Genocide are being captured and curated to support the centre's humanitarian agenda and associated values. We identify transferable curatorial concerns for human rights media communication amongst scholarly networks and public audiences worldwide, elucidating interaction design challenges for supportive ICT and contributing to HCI discourses on Value Sensitive Design and cultural engagement with sensitive materials.

The designers of mobile guides for museums and galleries face three major challenges: fostering rich interpretation, delivering deep personalization, and enabling a coherent social visit. We propose an approach to tackling all three simultaneously by inviting visitors to design an interpretation that is specifically tailored for a friend or loved one that they then experience together. We describe a trial of this approach at a contemporary art gallery, revealing how visitors designed personal and sometimes provocative experiences for people they knew well. We reveal how pairs of visitors negotiated these experiences together, showing how our approach could deliver intense experiences for both, but also required them to manage social risk. By interpreting our findings through the lens of 'gift giving' we shed new light on ongoing explorations of interpretation, personalization and social visiting within HCI.

Ethnographic study in two contrasting museums highlights a widespread but rarely documented challenge for CSCW design. Visitors' engagement with exhibits often ends prematurely due to the need to keep up with or attend to fellow group members. We unpack the mechanics of these kinds of phenomena revealing how the behaviours of summoning, pressurizing, herding, sidelining, and rounding up, lead to the responses of following, skimming and digging in. We show how the problem is especially challenging where young children are involved. As an initial prompt we explore two ways in which CSCW could help address this challenge: enabling a more fluid association between information and exhibits; and helping reconfigure the social nature of visiting.

Interactive digital technologies pervade our shared spaces in personal, mobile, infrastructural and other embedded forms. These changes challenge the ways we understand and investigate the relationships between people, computing and settings. Responding to this situation—where ubiquitous computing is not only personal but also public, and where digital interactions may happen anywhere — this special issue explores how HCI research can use the strengths of an intersection of theory, practice and innovation in order to best address this conjunction of interactive technologies, public spaces and people interacting with or within both. \n \nWith this shift to interaction happening in public spaces, people can no longer be seen as just ‘users’ but have to be understood as acting assemblages of bodies and technologies in the space they inhabit. This shift highlights the need to understand users in every setting—including those at desks and at work—as socially and culturally situated humans with agency. While this is not a new research development, this special issue speculates on and discusses how the shift to ‘everywhere interactions’ makes it important for research in human–computer interaction to reach beyond existing conventions. With this work comes a need to understand the interacting human as a situated body that is at any moment also a possible spectacle: as a body, a human and a user who engages with technology in response to the situation while also being a ‘performance’ for others to witness. Understanding people as actors in their context allows us to regard every user as a ‘performing body’ and a ‘performing subject’, and it enables us to analyse the performative aspects of interaction in many other situations than those where we design for actually staged performances in a defined performance space or stage. In this sense, ‘performative interaction’ is both concerned with technologies for on-stage performers using technologies as part of artistic expression, and an analytical frame for understanding every situation in which people engage with technologies (in public space). The question becomes: where and in which situations is this analytical frame relevant and useful?

We apply the HCI concept of trajectories to the design of a sculpture trail. We crafted a trajectory through each sculpture, combining textual and audio instructions to drive directed viewing, movement and touching while listening to accompanying music. We designed key transitions along the way to oscillate between moments of social interaction and isolated personal engagement, and to deliver official interpretation only after visitors had been given the opportunity to make their own. We describe how visitors generally followed our trajectory, engaging with sculptures and making interpretations that sometimes challenged the received interpretation. We relate our findings to discussions of sense-making and design for multiple interpretations, concluding that curators and designers may benefit from considering \'18trajectories of interpretation'.

User trials of mobile applications have followed a steady march out of the lab, and progressively further ''into the wild', recently involving ''app store'-style releases of software to the general public. Yet from our experiences on these mass participation systems and a survey of the literature, we identify a number of reported difficulties. We propose a hybrid methodology that aims to address these, by combining a global software release with a concurrent local trial. A phone-based game, created to explore the uptake and use of ad hoc peer-to-peer networking, was evaluated using this new hybrid trial method, combining a small-scale local trial (11 users) with a ''mass participation' trial (over 10,000 users). Our hybrid method offers many benefits, allowing locally observed findings to be verified, patterns in globally collected data to be explained and addresses ethical issues raised by the mass participation approach. We note trends in the local trial that did not appear in the larger scale deployment, and which would therefore have led to misleading results were the application trialed using ''traditional' methods alone. Based on this study and previous experience, we provide a set of guidelines to researchers working in this area.

Visions of the future are a common feature of discourse within ubiquitous computing and, more broadly, HCI. 'Envisioning', a characteristic future-oriented technique for design thinking, often features as significant part of our research processes in the field. This paper compares, contrasts and critiques the varied ways in which envisionings have been used within ubiquitous computing and traces their relationships to other, different envisionings, such as those of virtual reality. In unpacking envisioning, it argues primarily that envisioning should be foregrounded as a significant concern and interest within HCI. Foregrounding envisioning's frequent mix of fiction, forecasting and extrapolation, the paper recommends changes in the way we read, interpret and use envisionings through taking into account issues such as context and intended audience.

Field trials of experimental systems in the wild have developed into a standard method within HCI - testing new systems with groups of users in relatively unconstrained settings outside of the laboratory. In this paper we discuss methodological challenges in running user trials. Using a trial of trials we examined the practices of investigators and participants - documenting demand characteristics, where users adjust their behaviour to fit the expectations of those running the trial, the interdependence of how trials are run and the result they produce, and how trial results can be dependent on the insights of a subset of trial participants. We develop three strategies that researchers can use to leverage these challenges to run better trials.

This paper demonstrates how useful content can be generated as a by-product of an enjoyable mobile multiplayer game. In EyeSpy, players tag geographic locations with photos or text. By locating the places in which other players' tags were created and 'confirming' them, players earn points for themselves and verify the tags' locations. As a side effect of game-play, EyeSpy produces a collection of recognisable and findable geographic details, in the form of photographs and text tags, that can be repurposed to support navigation tasks. Two user trials of the game successfully produced an archive of geo-located photographs and tags, and in a follow-up experiment we compared performance in a navigation task using photographs from the game, with geo-referenced photos collected from the Flickr website. Our experiences with EyeSpy support reflection upon the design challenges presented by 'human computation' and the production of usable by-products through mobile game-play.

Fairground: Thrill Laboratory was a series of live events that augmented the experience of amusement rides. A wearable telemetry system captured video, audio, heart-rate and acceleration data, streaming them live to spectator interfaces and a watching audience. In this paper, we present a study of this event, which draws on video recordings and post-event interviews, and which highlights the experiences of riders, spectators and ride operators. Our study shows how the telemetry system transformed riders into performers, spectators into an audience, and how the role of ride operator began to include aspects of orchestration, with the relationship between all three roles also transformed. Critically, the introduction of a telemetry system seems to have had the potential to re-connect riders/performers back to operators/orchestrators and spectators/audience, re-introducing a closer relationship that used to be available with smaller rides. Introducing telemetry to a real-world situation also creates significant complexity, which we illustrate by focussing on a moment of perceived crisis.

By considering the spatial character of sensor-based interactive systems, this paper investigates how discussions of seams and seamlessness in ubiquitous computing neglect the complex spatial character that is constructed as a side-effect of deploying sensor technology within a space. Through a study of a torch (aka 'flashlight') based interface, we develop a framework for analysing this spatial character generated by sensor technology. This framework is then used to analyse and compare a range of other systems in which sensor technology is used, in order to develop a design spectrum that contrasts the revealing and hiding of a system's structure to users. Finally, we discuss the implications for interfaces situated in public spaces and consider the benefits of hiding structure from users.

Mobile experiences that take place in public settings such as on city streets create new opportunities for interweaving the fictional world of a performance or game with the everyday physical world. A study of a touring performance reveals how designers generated excitement and dramatic tension by implicating bystanders and encouraging the (apparent) crossing of normal boundaries of behaviour. The study also shows how designers dealt with associated risks through a process of careful orchestration. Consequently, we extend an existing framework for designing spectator interfaces with the concept of performance frames, enabling us to distinguish audience from bystanders. We conclude that using ambiguity to blur the frame can be a powerful design tactic, empowering players to willingly suspend disbelief, so long as a safety-net of orchestration ensures that they do not stray into genuine difficulty.

Interaction is increasingly a public affair, taking place in our theatres, galleries, museums, exhibitions and on the city streets. This raises a new design challenge for HCI - how should spectators experience a performer's interaction with a computer? We classify public interfaces (including examples from art, performance and exhibition design) according to the extent to which a performer's manipulations of an interface and their resulting effects are hidden, partially revealed, fully revealed or even amplified for spectators. Our taxonomy uncovers four broad design strategies: 'secretive,' where manipulations and effects are largely hidden; 'expressive,' where they tend to be revealed enabling the spectator to fully appreciate the performer's interaction; 'magical,' where effects are revealed but the manipulations that caused them are hidden; and finally 'suspenseful,' where manipulations are apparent but effects are only revealed as the spectator takes their turn.