Group snacking contexts are typically unstructured and frequently associated with the consumption of snack product FMCGs (fast-moving consumer goods). Snacks are generally low value, shared and potentially over consumed. To explore the potential of digital interventions to playfully elevate the value of these snacks, we created a sharing snack bowl technology probe embedding simple game mechanics to track individual turns for taking a snack. This paper presents both in-lab and home studies where participants used the snack bowl whilst simultaneously playing a quiz card game. Findings from thematic analysis revealed how the snack bowl elicited togetherness, reflection, and social pressure whilst also disrupting group snacking habits. Our contributions include implications for reconfiguring snacking and enhancing the value of low-cost FMCGs through ludic design elements, and augmenting everyday tangible objects for use in group settings.

Losing Her Voice is a new opera which highlights the challenges of subtly interweaving digital technologies into established cultural forms. Audience members were encouraged to use their own mobile phones to interact with on-stage projections before, during and after the performance. We chart the trajectories of participation that were designed into the premiere performances of this work, and how these unfolded in practice. We identify the strategies that were effective to: encourage the adoption of the mobile app; interweave use with the other elements of the opera performance; make it consistent with the content; and ensure it complemented but was not essential to the show. We highlight the way in which three canonical trajectories must be woven together in this experience: the standard trajectory of “a night at the opera”; the dramatic arc of the specific work, and the audience member's use of their own device.

Virtual human technologies are now being widely explored as therapy tools for mental health disorders including depression and anxiety. These technologies leverage the ability of the virtual agents to engage in naturalistic social interactions with a user to elicit behavioural expressions which are indicative of depression and anxiety. Research efforts have focused on optimising the human-like expressive capabilities of the virtual human, but less attention has been given to investigating the effect of virtual human mediation on the expressivity of the user. In addition, it is still not clear what an optimal task is or what task characteristics are likely to sustain long term user engagement. To this end, this paper describes the design and evaluation of virtual human-mediated tasks in a user study of 56 participants. Half the participants complete tasks guided by a virtual human, while the other half are guided by text on screen. Self-reported PHQ9 scores, biosignals and participants' ratings of tasks are collected. Findings show that virtual-human mediation influences behavioural expressiveness and this observation differs for different depression severity levels. It further shows that virtual human mediation improves users' disposition towards tasks.

Access to healthcare advice is crucial to promote healthy societies. Many factors shape how access might be constrained, such as economic status, education or, as the COVID-19 pandemic has shown, remote consultations with health practitioners. Our work focuses on providing pre/post-natal advice to maternal women. A salient factor of our work concerns the design and deployment of embodied conversation agents (ECAs) which can sense the (health) literacy of users and adapt to scaffold user engagement in this setting. We present an account of a Wizard of Oz user study of 'ALTCAI', an ECA with three modes of interaction (i.e., adaptive speech and text, adaptive ECA, and non-adaptive ECA). We compare reported engagement with these modes from 44 maternal women who have differing levels of literacy. The study shows that a combination of embodiment and adaptivity scaffolds reported engagement, but matters of health-literacy and language introduce nuanced considerations for the design of ECAs.

Summary In this paper, we present the study of interactional arrangements that support the collaboration of headquarters (HQ), field responders, and a computational planning agent in a time‐critical task setting created by a mixed‐reality game. Interactional arrangements define the extent to which control is distributed between the collaborative parties. We provide 2 field trials, one to study an “on‐the‐loop” arrangement in which HQ monitors and intervenes in agent instructions to field players on demand and the other, to study a version that places HQ more tightly “in‐the‐loop.” The studies provide an understanding of the sociotechnical collaboration between players and the agent in these interactional arrangements by conducting interaction analysis of video recordings and game log data. The first field trial focuses on the collaboration of field responders with the planning agent. Findings highlight how players negotiate the agent guidance within the social interaction of the collocated teams. The second field trial focuses on the collaboration between the automated planning agent and the HQ. We find that the human coordinator and the agent can successfully work together in most cases, with human coordinators inspecting and “correcting” the agent‐proposed plans. Through this field trial‐driven development process, we generalise interaction design implications of automated planning agents around the themes of supporting common ground and mixed‐initiative planning.

As computer interfaces spread across and even into our bodies, so we find ourselves engaged in ever more deeply connected bodily interactions. From the mouse and keyboard, to wearables and gestural...

This article presents the results of a study based on a group of participants' interactions with an experimental sound installation at the National Science and Media Museum in Bradford, UK. The installation used audio augmented reality to attach virtual sound sources to a vintage radio receiver from the museum's collection, with a view to understanding the potentials of this technology for promoting exploration and engagement within museums and galleries. We employ a practice-based design ethnography, including a thematic analysis of our participants' interactions with spatialised interactive audio, and present an identified sequence of interactional phases. We discuss how audio augmented artefacts can communicate and engage visitors beyond their traditional confines of line-of-sight, and how visitors can be drawn to engage further, beyond the realm of their original encounter. Finally, we provide evidence of how contextualised and embodied interactions, along with authentic audio reproduction, evoked personal memories associated with our museum artefact, and how this can promote interest in the acquisition of declarative knowledge. Additionally, through the adoption of a functional and theoretical aura-based model, we present ways in which this could be achieved, and, overall, we demonstrate a material object's potential role as an interface for engaging users with, and contextualising, immaterial digital audio archival content.

Hybrid gifting combines physical artefacts and experiences with digital interactivity to generate new kinds of gifts. Our review details how gifting is a complex social phenomenon and how digital gifting is less engaging than physical gifting for both givers and receivers. Employing a Research Through Design approach, we developed a portfolio of four hybrid gifting experiences: an augmented advent calendar; edible music tracks; personalized museum tours; and a narrated city walk. Our reflection addresses three concepts: hybrid wrapping where physical gifts become wrapped in digital media and vice versa; the importance of effortful interactions that are visible and pleasurable; and the need to consider social obligation, including opportunities for acknowledgement and reciprocation, dealing with embarrassment, and recognizing the distinction between giving and sharing. Our concepts provide guidance to practitioners who wish to design future gifting experiences while helping HCI researchers engage with the concept of gifting in a nuanced way.

Failure is a common artefact of challenging experiences, a fact of life for interactive systems but also a resource for aesthetic and improvisational performance. We present a study of how three professional pianists performed an interactive piano composition that included playing hidden codes within the music so as to control their path through the piece and trigger system actions. We reveal how apparent failures to play the codes occurred for diverse reasons including mistakes in their playing, limitations of the system, but also deliberate failures as a way of controlling the system, and how these failures provoked aesthetic and improvised responses from the performers. We propose that creative and performative interfaces should be designed to enable aesthetic failures and introduce a taxonomy that compares human approaches to failure with approaches to capable systems, revealing new creative design strategies of gaming, taming, riding and serving the system.

Guitars are physical instruments that require skillful two-handed use. Their use is also supported by diverse digital and physical resources, such as videos and chord charts. To understand the challenges of interacting with supporting resources at the same time as playing we conducted an ethnographic study of the preparation activities of working musicians. We observe successive stages of individual and collaborative preparation, in which working musicians engage with a diverse range of digital and physical resources to support their preparation. Interaction with this complex ecology of digital and physical resources is finely interwoven into their embodied musical practices, which are usually encumbered by having their instrument in hand, and often by playing. We identify challenges for augmenting guitars within the rehearsal process by supporting interaction that is encumbered, contextual and connected, and suggest a range of possible responses.

Self-report questionnaires like PHQ-9 and GAD-7 are often used in the field of psychology to detect mental health problems and measure their severity. Their validity has been well established by a number of previous studies. However, most previous studies have used self-administration method to study their validity. In the context of automating the administering of questionnaires as a part of an interaction scenario led by a virtual human, we investigate if the virtual human administration of these questionnaires can be considered equivalent to the self-administration of these questionnaires (through an electronic form). Additionally, we also examine the equivalence when the virtual human is replaced by a real human. The interaction with real human is studied in two different modes: face-to-face and through a video-conferencing link. Statistical analysis of the scores obtained from our user study (consisting of 55 participants) revealed that human/virtual-human administered questionnaires can be considered practically equivalent to self administered ones. In most cases, the differences in the scores from self-administered questionnaires and human/virtual-human administered questionnaires, were found to be smaller than any effect size which could be considered practically significant.

We report on the design, premiere and public evaluation of a multifaceted audience interface for a complex non-linear musical performance called Climb! which is particularly suited to being experienced more than once. This interface is designed to enable audiences to understand and appreciate the work, and integrates a physical instrument and staging, projected visuals, personal devices and an online archive. A public premiere concert comprising two performances of Climb! revealed how the audience reoriented to the second performance through growing understanding and comparison to the first. Using trajectories as an analytical framework for the audience 'journey' made apparent: how the trajectories of a single performance are embedded within the larger trajectories of a concert and the creative work as a whole; the distinctive demands of understanding and interpretation; and the potential of the archive in enabling appreciation across repeated performances.

We present our case study on gifting digital music, The Rough Mile, as an example of a Framework of Immersive Practice, intended for researchers and practitioners in HCI and interaction design. Although immersion is a frequently used term in the HCI and related literatures, we find no definitions or frameworks that are robust enough to capture the full range of multi-sensory, emotional, and cognitive engagement that the richest of these experiences can entail. We therefore turn to the theatrical performance literature to distil a theory-based framework of practices that can apply to interdisciplinary projects as well as works with an entirely aesthetic aim. The design choices and findings of The Rough Mile are presented in terms of this framework, leading to a discussion of the design guidelines that can shape its use in any HCI or interaction design project aiming for a deep, personal engagement through technology.

We report lessons from iteratively developing a music recognition system to enable a wide range of musicians to embed musical codes into their typical performance practice. The musician composes fragments of music that can be played back with varying levels of embellishment, disguise and looseness to trigger digital interactions. We collaborated with twenty-three musicians, spanning professionals to amateurs and working with a variety of instruments. We chart the rapid evolution of the system to meet their needs as they strove to integrate music recognition technology into their performance practice, introducing multiple features to enable them to trade-off reliability with musical expression. Collectively, these support the idea of deliberately introducing "looseness" into interactive systems by addressing the three key challenges of control, feedback and attunement, and highlight the potential role for written notations in other recognition-based systems.

In this paper we use results from two ethnographic studies of the music production process to examine some key issues regarding how work is currently accomplished in studio production environments. These issues relate in particular to workflows and how metadata is adapted to the specific needs of specific parts of the process. We find that there can be significant tensions between how reasoning is applied to metadata at different stages of production and that this can lead to overheads where metadata has to be either changed or created anew to make the process work. On the basis of these findings we articulate some of the potential solutions we are now examining. These centre in particular upon the notions of Digital/Dynamic Musical Objects and flexible metadata shells.

This paper outlines the IoT Databox model as a means of making the Internet of Things (IoT) accountable to individuals. Accountability is a key to building consumer trust and mandated in data protection legislation. We briefly outline the `external' data subject accountability requirement specified in actual legislation in Europe and proposed legislation in the US, and how meeting requirement this turns on surfacing the invisible actions and interactions of connected devices and the social arrangements in which they are embedded. The IoT Databox model is proposed as an in principle means of enabling accountability and providing individuals with the mechanisms needed to build trust in the IoT.

We explore the crafting of interactive decoration for everyday artefacts. This involves adorning them with decorative patterns that enhance their beauty while triggering digital interactions when scanned with cameras. These are realized using an existing augmented reality technique that embeds computer readable codes into the topological structures of hand-drawn patterns. We describe a research through design process that engaged artisans to craft a portfolio of interactive artefacts, including ceramic bowls, embroidered gift cards, fabric souvenirs, and an acoustic guitar. We annotate this portfolio with reflections on the crafting process, revealing how artisans addressed pattern, materials, form and function, and digital mappings throughout their craft process. Further reflection on our portfolio reveals how they bridged between human and system perceptions of visual patterns and engaged in a deep embedding of digital interactions into physical materials. Our findings demonstrate the potential for interactive decoration, distilling the craft knowledge involved in creating aesthetic and functional decoration, highlight the need for transparent computer vision technologies, and raise wider issues for HCI’s growing engagement with craft.

We explore how physical artefacts can be connected to digital records of where they have been, who they have encountered and what has happened to them, and how this can enhance their meaning and utility. We describe how a travelling technology probe in the form of an augmented acoustic guitar engaged users in a design conversation as it visited homes, studios, gigs, workshops and lessons, and how this revealed the diversity and utility of its digital record. We describe how this record was captured and flexibly mapped to the physical guitar and proxy artefacts. We contribute a conceptual framework for accountable artefacts that articulates how multiple and complex mappings between physical artefacts and their digital records may be created, appropriated, shared and interrogated to deliver accounts of provenance and use as well as methodological reflections on technology probes.

Listening to music on the move is an everyday activity for many people. This paper proposes geotracks and geolists, music tracks and playlists of existing music that are aligned and adapted to specific journeys. We describe how everyday walking journeys such as commutes to work and existing popular music tracks can each be analysed, decomposed and then brought together, using musical adaptations including skipping and repeating parts of tracks, dynamically remixing tracks and cross-fades. Using a naturalistic experiment we compared walking while listening to geotracks (dynamically adapted using GPS location information) to walking while listening to a fixed playlist. Overall, participants enjoyed the walk more when listening to the adaptive geotracks. However adapting the lengths of tracks appeared to detract from the experience of the music in some situations and for some participants, revealing trade-offs in achieving fine-grained alignment of music and walking journeys.

This paper offers a sociological perspective on data protection regulation and its relevance to design. From this perspective, proposed regulation in Europe and the USA seeks to create a new economic actor—the consumer as personal data trader—through new legal frameworks that shift the locus of agency and control in data processing towards the individual consumer or “data subject”. The sociological perspective on proposed data regulation recognises the reflexive relationship between law and the social order, and the commensurate needs to balance the demand for compliance with the design of computational tools that enable this new economic actor. We present the Databox model as a means of providing data protection and allowing the individual to exploit personal data to become an active player in the emerging data economy.

In this paper we show how -- with the aid of enabling technology -- creative Location Based Experiences can be developed for visitors by non-technical professionals from the cultural heritage sector. We look at how these "Place Experts" approach and adopt web technologies to create and publish experiences including the roles they take on, the processes they adopt, and the way they appropriate the technology. We describe our short and long-term research engagements with the cultural heritage sector over the last three years and introduce Wander Anywhere, the website developed to enable this research. We find that place experts typically follow a four stage process in their engagement with location-based experiences, moving from comprehension to translation, development and finally approval. We suggest implications for the processes and technologies that might be employed by others seeking to support a similar type of engagement.

This paper reports on a study of 4CG, a cooperative enterprise located in rural Wales. 4CG operates for the good of the local economy and seeks to diversify its commercial portfolio through the creation of an online shop retailing goods and services from local suppliers. The paper compliments prior field studies focusing on rural enterprise and the challenges posed by this category of business for IT support. The current study is motivated by 4CG’s interest in setting up a local online shop and explicates the organisational issues that this venture turns upon and elaborates for broader sustainability agendas.

We explore the ethical implications of HCI's turn to the ‘cultural’. This is motivated by an awareness of how cultural applications, in our case interactive performances, raise ethical issues that may challenge established research ethics processes. We review research ethics, HCI's engagement with ethics and the ethics of theatrical performance. Following an approach grounded in Responsible Research Innovation, we present the findings from a workshop in which artists, curators, commissioners, and researchers explored ethical challenges revealed by four case studies. We identify six ethical challenges for HCI's engagement with cultural applications: transgression, boundaries, consent, withdrawal, data, and integrity. We discuss two broader implications of these: managing tensions between multiple overlapping ethical frames; and the importance of managing ethical challenges during and after an experience as well as beforehand. Finally, we discuss how our findings extend previous discussions of Value Sensitive Design in 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.

Participate was a 3-year collaboration between industry and academia to explore how mobile, Web and broadcast technologies could combine to deliver environmental campaigns. In a series of pilot projects, schools used mobile sensors to enhance science learning; visitors to an ecological attraction employed mobile phones to access and generate locative media; and the public played a mobile phone game that challenged their environmental behaviours. Key elements of these were carried forward into an integrated trial in which participants were assigned a series of environmental missions as part of an overarching narrative that was delivered across mobile, broadcast and Web platforms. These experiences use a three-layered structure for campaigns that draw on experts, local groups and the general public, who engage through a combination of playful characterisation and social networking.

We explore the approach of performance-led research in the wild in which artists drive the creation of novel performances with the support of HCI researchers that are then deployed and studied at public performance in cultural settings such as galleries, festivals and on the city streets. We motivate the approach and then describe how it consists of three distinct activities -- practice, studies and theory -- that are interleaved in complex ways through nine different relationships. We present a historical account of how the approach has evolved over a fifteen-year period, charting the evolution of a complex web of projects, papers, and relationships between them. We articulate the challenges of pursuing each activity as well as overarching challenges of balancing artistic and research interests, flexible management of relationships, and finally ethics.

We argue for deliberately and systematically creating uncomfortable interactions as part of powerful cultural experiences. We identify the potential benefits of uncomfortable interactions under the general headings of entertainment, enlightenment and sociality. We then review artworks and performances that have employed discomfort, including two complementary examples from the worlds of entertainment and performance. From this, we articulate a suite of tactics for designing four primary forms of discomfort referred to as visceral, cultural, control and intimate. We discuss how moments of discomfort need to be embedded into an overall experience which requires a further consideration of the dramatic acts of exposition, rising action, climax, falling action, and dénouement. Finally, we discuss an ethical framework for uncomfortable interactions which leads us to revisit key issues of consent, withdrawal, privacy and risk.

Ethnographic studies have played a key part in informing the design and development of a multitude of ubiquitous systems, from control room systems to pervasive games. While other papers have often focused on systems developed for urban contexts, this paper presents the initial findings of a study that focuses on a rural produce market in West Wales as a site for ubiquitous multimedia system-based intervention, digital economic considerations and co-design. The findings relate to the initial ethnographic fieldwork, digital-economic considerations for the site, the evolution of a participatory design strategy for developing a Market Portal and - importantly -- the way that these are informing the design of the ubiquitous technologies relating to the Market Portal.

We investigate whether opportune moments to deliver notifications surface at the endings of episodes of mobile interaction (making voice calls or receiving SMS) based on the assumption that the endings collocate with naturally occurring breakpoint in the user's primary task. Testing this with a naturalistic experiment we find that interruptions (notifications) are attended to and dealt with significantly more quickly after a user has finished an episode of mobile interaction compared to a random baseline condition, supporting the potential utility of this notification strategy. We also find that the workload and situational appropriateness of the secondary interruption task significantly affect subsequent delay and completion rate of the tasks. In situ self-reports and interviews reveal complexities in the subjective experience of the interruption, which suggest that a more nuanced classification of the particular call or SMS and its relationship to the primary task(s) would be desirable.

An ethnographic study reveals how professional artists created a spectator interface for the interactive game Day of the Figurines, designing the size, shape, height and materials of two tabletop interfaces before carefully arranging them in a local setting. We also show how participants experienced this interface. We consider how the artists worked with a multi-scale notion of interactional trajectory that combined trajectories through individual displays, trajectories through a local ecology of displays, and trajectories through an entire experience. Our findings shed light on discussions within HCI concerning interaction with tangible and tabletop displays, spectator interfaces, ecologies of displays, and trajectories through cultural experiences.

In this paper we investigate effects of the content of interruptions and of the time of interruption delivery on mobile phones. We review related work and report on a naturalistic quasi-experiment using experience-sampling that showed that the receptivity to an interruption is influenced by its content rather than by its time of delivery in the employed modality of delivery - SMS. We also examined the underlying variables that increase the perceived quality of content and found that the factors interest, entertainment, relevance and actionability influence people's receptivity significantly. Our findings inform system design that seeks to provide context-sensitive information or to predict interruptibility and suggest the consideration of receptivity as an extension to the way we think and reason about interruptibility.

One-to-one technology involves equipping each child with a computing device that provides personalized learning tools. While one-to-one learning is showing promise in classrooms, it has revealed problems, including management of the technology-enabled classroom, lack of support for collaborative and whole class working, the design of lessons that switch easily between activities, and difficulty in re-use of lesson components. In this paper we describe the SceDer system to orchestrate learning with one-to-one technologies. It provides an authoring system for teachers to design lessons, an interchange language to describe lesson sequences and resources, and a delivery system that enables the teacher to manage collaborative one-to-one learning in the classroom. The system has been tested in school classrooms and the results show that it is effective in managing a fluid movement between individual, group, and whole class learning activities.

This paper presents the evolution of a tool to support the rapid prototyping of hybrid museum experiences by domain professionals. The developed tool uses visual markers to associate digital resources with physical artefacts. We present the iterative development of the tool through a user centred design process and demonstrate its use by domain experts to realise two distinct hybrid exhibits. The process of design and refinement of the tool highlights the need to adopt an experience oriented approach allowing authors to think in terms of the physical and digital "things" that comprise a hybrid experience rather than in terms of the underlying technical components.

Householders are increasingly adopting home networking as a solution to the demands created by the presence of multiple computers, devices, and the desire to access the Internet. However, current network solutions are derived from the world of work (and initially the military) and provide poor support for the needs of the home. We present the key findings to emerge from empirical studies of home networks in the UK and US. The studies reveal two key kinds of work that effective home networking relies upon: one, the technical work of setting up and maintaining the home network, and the other, the collaborative and socially organized work of the home which the network is embedded in and supports. The two are thoroughly intertwined and rely upon one another for their realization, yet neither is adequately supported by current networking technologies and applications. Explication of the “work to make the home network work” opens up the design space for the continued integration of the home network in domestic life and elaboration of future support. Key issues for development include the development of networking facilities that do not require advanced networking knowledge, that are flexible and support the local social order of the home and the evolution of its routines, and which ultimately make the home network visible and accountable to household members.

Ethnography has become a staple feature of IT research over the last twenty years, shaping our understanding of the social character of computing systems and informing their design in a wide variety of settings. The emergence of ubiquitous computing raises new challenges for ethnography however, distributing interaction across a burgeoning array of small, mobile devices and online environments which exploit invisible sensing systems. Understanding interaction requires ethnographers to reconcile interactions that are, for example, distributed across devices on the street with online interactions in order to assemble coherent understandings of the social character and purchase of ubiquitous computing systems. We draw upon four recent studies to show how ethnographers are replaying system recordings of interaction alongside existing resources such as video recordings to do this and identify key challenges that need to be met to support ethnographic study of ubiquitous computing in the wild.

Movements of interfaces can be analyzed in terms of whether they are expected, sensed, and desired. Expected movements are those that users naturally perform; sensed are those that can be measured by a computer; and desired movements are those that are required by a given application. We show how a systematic comparison of expected, sensed, and desired movements, especially with regard to how they do not precisely overlap, can reveal potential problems with an interface and also inspire new features. We describe how this approach has been applied to the design of three interfaces: pointing flashlights at walls and posters in order to play sounds; the Augurscope II, a mobile augmented reality interface for outdoors; and the Drift Table, an item of furniture that uses load sensing to control the display of aerial photographs. We propose that this approach can help to build a bridge between the analytic and inspirational approaches to design and can help designers meet the challenges raised by a diversification of sensing technologies and interface forms, increased mobility, and an emerging focus on technologies for everyday life.

Successfully staging a mixed reality game in which online players are chased through a virtual city by runners located in the real world requires extensive orchestration work. An ethnographic study shows how this concerted achievement extends beyond the control room to the runners on the street. This, in turn, suggests the need to 'decentralize' orchestration and develop support for collaboration 'on the ground'. The study leads to design proposals for orchestration interfaces for mobile experiences that augment situational awareness and surreptitious monitoring among mobile participants and support troubleshooting in situations where participants are disconnected or are unable to access positioning systems such as GPS.

Delay is an unavoidable reality in collaborative environments. We propose an approach to dealing with delay in which 'decorators' are introduced into the interface. Decorators show the presence, magnitude and effects of delay so that participants can better understand its consequences and adopt their own natural coping strategies. Two experiments with different decorators show that this approach can significantly reduce errors in specific collaborative activities. We conclude that revealing delays is one way in which groupware can benefit from accepting and working with the reality of distributed systems, rather than trying to maintain the illusion of copresent interaction.

In this paper we discuss the use of models of space in the building of mixed-reality systems. By model of space we mean a geometric or symbolic description associated with a physical space. We outline several types of model that exist, how they are surveyed and authored, how they are represented to the users and how they are supported by middleware and sensors. We show that systems often contain numerous models of space and we discuss the issues in maintaining or reifying assumptions about transformations between models. We illustrate these ideas by describing the implementation of a collaborative mixed-reality system that allows users to experience a museum in three modalities: physically colocated visitor with personal digital assistant guide, virtual reality visitor and Web visitor.

My Grid is an e-Science Grid project that aims to help biologists and bioinformaticians to perform workflow-based in silico experiments, and help them to automate the management of such workflows through personalisation, notification of change and publication of experiments. In this paper, we describe the architecture of my Grid and how it will be used by the scientist. We then show how my Grid can benefit from agents technologies. We have identified three key uses of agent technologies in my Grid: user agents, able to customize and personalise data, agent communication languages offering a generic and portable communication medium, and negotiation allowing multiple distributed entities to reach service level agreements.

We describe two games in which online participants collaborated with mobile participants on the city streets. In the first, the players were online and professional performers were on the streets. The second reversed this relationship. Analysis of these experiences yields new insights into the nature of context. We show how context is more socially than technically constructed. We show how players exploited (and resolved conflicts between) multiple indications of context including GPS, GPS error, audio talk, ambient audio, timing, local knowledge and trust. We recommend not overly relying on GPS, extensively using audio, and extending interfaces to represent GPS error.

The augurscope is a portable mixed reality interface for outdoors. A tripod-mounted display is wheeled to different locations and rotated and tilted to view a virtual environment that is aligned with the physical background. Video from an onboard camera is embedded into this virtual environment. Our design encompasses physical form, interaction and the combination of a GPS receiver, electronic compass, accelerometer and rotary encoder for tracking. An initial application involves the public exploring a medieval castle from the site of its modern replacement. Analysis of use reveals problems with lighting, movement and relating virtual and physical viewpoints, and shows how environmental factors and physical form affect interaction. We suggest that problems might be accommodated by carefully constructing virtual and physical content

Distributed Partial Mixing is an approach to creating a distributed audio service that supports optimisation of bandwidth utilization across multiple related audio streams (e.g. from concurrently active audio sources) while maintaining fairness to TCP traffic in best effort networks. Rate adaptation of streamed audio is difficult because of its rate sensitivity, the relatively limited range of encoding bandwidths available and the potential impact on the end user of rate-adaptation artefacts (such as changes of encoding). This paper describes and demonstrates how our design combines TCP-fairness with the stability that is desirable for streaming audio and other rate sensitive media. In particular, our design combines: a distributed multi-stream management/mixing architecture, loss event and round-trip time monitoring, rate limiting based on a TCP rate equation, tuned increase and decrease strategies and a loss-driven network probing mode. Experimental validation is performed over a wide range of network conditions including against various congesting levels, TCP and independent DPM traffic.

Temporal links allow recordings of multi-user sessions to be dynamically inserted into current virtual worlds in a flexible and principled way. We explore key applications of temporal links, showing how they can add new content to virtual worlds, support usability and system evaluation, and link VR to other media such as film and television. These applications illustrate just some of the possibilities of a ubiquitous and flexible record and replay facility such as temporal links. Building on our experience of implementing temporal links in the MASSIVE-3 system, we identify key requirements for system architectures that wish to support an equivalent mechanism.

Many VR platforms emphasise extensibility in order to support as wide a range of applications as possible. The current trend is to move this extensibility to lower levels of the system, in order to support extensibility of infrastructure mechanisms such as networking protocols. This kind of extensibility allows the run-time of the virtual environment system to evolve even while the system is running. This paper presents a new virtual environment platform that allows multiple infrastructure mechanisms to be added to and co-exist within the running system, with different elements of the virtual world using different mechanisms. This allows the virtual environment system to efficiently support a wider range of applications by, for example, having only certain virtual objects use conservative consistency and persistence. It can also optimise the performance of the CVE by tailoring the infrastructure mechanisms according to the different roles played by different objects in the virtual environment.

We describe an audio service for CVEs, designed to support many people speaking simultaneously and to operate across the Internet. Our service exploits a technique called Distributed Partial Mixing (DPM) to dynamically adapt to varying numbers of speakers and network congestion. Our DPM implementation dynamically manages the trade-off between congestion and audio quality when compared to the approaches of peer-to-peer forwarding and total mixing in a way that is fair to the TCP protocol and so operates as a "good Internet citizen". This paper focuses on the large-scale deployment of DPM over wide area networks. In particular we raise and examine the issues when deploying DPM within the context of large dynamic environments. We argue that DPM paradigm remains feasible and desirable in such environments.

We present four contrasting interfaces to allow multiple viewers to explore 3D recordings of dramas in on-line virtual worlds. The first is an on-line promenade performance to an audience of avatars. The second is a form of immersive cinema, with multiple simultaneous viewpoints. The third is a tabletop projection surface that allows viewers to select detailed views from a bird's-eye overview. The fourth is a linear television broadcast created by a director or editor. A comparison of these examples shows how a viewing audience can exploit four general resources - interactivity, influence, space, and time - to make sense of complex, non-linear virtual drama. These resources provide interaction designers with a general framework for defining the relationship between the audience and the 3D content.

A study of a professional touring mixed reality performance called Desert Rain yields insights into how performers orchestrate players' engagement in an interactive experience. Six players at a time journey through an extended physical and virtual set. Each sees a virtual world projected onto a screen made from a fine water spray. This acts as a traversable interface, supporting the illusion that performers physically pass between real and virtual worlds. Live and video-based observations of Desert Rain, coupled with interviews with players and the production team, have revealed how the performers create conditions for the willing suspension of disbelief, and how they monitor and intervene in the players experience without breaking their engagement. This involves carefully timed performances and “off-face” and “virtual” interventions. In turn, these are supported by the ability to monitor players' physical and virtual activity through asymmetric interfaces.

We describe a pilot study of the use of a mixed reality environment for distributed presentations involving virtual and physical audiences and speakers. Our aims were to establish mutual awareness between all participants; to present physical and virtual worlds as being spatially integrated; and to support moderate sized audiences. We used a mixed reality boundary to join a physical space to a collaborative virtual environment so that the two appeared to be adjacent but distinct components of a single space. Two presentations were staged to a mixed physical and virtual audience, one by a virtual speaker and one by a physical speaker. Each presentation was followed by a question and answer session. Qualitative analysis of semi-structured interviews and video recordings revealed that some degree of mutual awareness was established between participants and that physical participants may have viewed the environment as being more spatially integrated than virtual participants. We propose that improving avatars and video textures in the virtual environment may further enhance the experience.

Traversable interfaces establish the illusion that virtual and physical worlds are joined together and that users can physically cross from one to the other. Our design for a traversable interface combines work on tele-embodiment, mixed reality boundaries and virtual environments. It also exploits non-solid projection surfaces, of which we describe four examples. Our design accommodates the perspectives of users who traverse the interface and also observers who are present in the connected physical and virtual worlds, an important consideration for performance and entertainment applications. A demonstrator supports encounters between members of our laboratory and remote visitors.

Virtual reality (VR) currently lacks the kinds of sophisticated production technologies that are commonly available for established media such as video and audio. This paper introduces the idea of temporal links, which provide a flexible mechanism for replaying past or recent recordings of virtual environments within other real-time virtual environments. Their flexibility arises from a combination of temporal, spatial and presentational properties. Temporal properties determine the relationship between time in a live environment and time in a recording, including the apparent speed and direction of replay. Spatial properties determine the spatial relationship between the environment and the recording. Presentational properties determine the appearance of the recording within the environment. These properties may be fixed, dynamically varied by an application, or directly controlled in real-time by users. Consequently, temporal links have a wide variety of potential uses, including supporting post-production tools for virtual environments, post-exercise debriefing in training simulators, and asynchranous communication such as VR email, as well as providing new forms of content for virtual worlds that refer to past activity. We define temporal links and their properties and describe their implementation in the MASSIVE-3 Collaborative Virtual Environment (CVE) system, focusing on the underlying record and replay mechanisms. We also demonstrate applications for adding new content to an existing virtual world, and a VR post-production editor.

In the MASSIVE-3 system we have adopted the locale approach to organising large virtual environments, and extended it, integrating the notion of awareness, adding support for alternative representations of locales, integrating functional and organisation data management and introducing a flexible framework for defining dynamic locale selection policies.

Inhabited television combines collaborative virtual environments (CVEs) with broadcast television so that on-line audiences can participate in television shows within shared virtual worlds. We describe a series of experiments with inhabited television, beginning with the NOWninety6 poetry performance, The Mirror, and Heaven & Hell—Live. These early experiments raised fundamental questions for inhabited television concerning the extent to which it is possible to establish fast-paced social interaction within a CVE, and to which it is possible to produce a coherent and engaging broadcast of this action. We then present a fourth more recent experiment, Out of This World, that directly addressed these questions. We describe how the formulation of inhabited television design principles, combined with the use of dedicated production software for scripting and directing a show and for controlling virtual cameras, enabled us to create a fast-moving and more coherent experience.

This paper explores and evaluates the support for object-focused interaction provided by a desktop Collaborative Virtual Environment. An experimental “design” task was conducted, and video recordings of the participants' activities facilitated an observational analysis of interaction in, and through, the virtual world. Observations include: problems due to “fragmented” views of embodiments in relation to shared objects; participants compensating with spoken accounts of their actions; and difficulties in understanding others' perspectives. Implications and proposals for the design of CVEs drawn from these observations are: the use of semidistorted views to support peripheral awareness; more explicit or exaggerated representations of actions than are provided by pseudohumanoid avatars; and navigation techniques that are sensitive to the actions of others. The paper also presents some examples of the ways in which these proposals might be realized.

We present a QoS architecture for collaborative virtual environments (CVEs), focusing on the management of streamed video within shared virtual worlds. Users express QoS requirements by negotiating levels of mutual awareness using our previously defined spatial model of interaction. The architecture uses these awareness values as part of dynamic QoS management. A key aspect of the architecture is that it maintains a balance between the needs of a group of users as a whole (e.g., which streams are admitted onto a shared network) versus those of individual users within the group (e.g., which streams are subscribed to by a local host). We walk through a demonstration scenario, a virtual shopping mall, to show the architecture at work.

Inhabited Television" combines multiuser virtual environments with television, so that online audience-members can participate in TV shows staged in a virtual world.It is presented simultaneously both to conventional passive viewers and to online participants.In many cases it benefits from being broadcast live.This paper is based on our fourth major experiment with Inhabited TV, a live virtual game show called "Out Of This World".For this event we adopted non-automated approaches to camera control and mixing to allow an exploration of appropriate forms of presentation for inhabited television.We describe the techniques which were used to create and enhance the live video output which was produced during the show: appropriate world design; dynamic constraints on participant movements; and a performance-oriented virtual camera control interface.This camera control interface includes explicit support for a range of spatial and temporal control styles.We also give evaluative feedback on the camera control interface and the event's (television-based) approach to mixing and directing, drawing on a social scientific field study conducted on-site during the preparation for, and performances of, the show.

To allow the number of simultaneous participants and applications to grow, many Collaborative Virtual Environment (CVE) platforms are combining ideas such as loose consistency, absence of central servers and world sub-partitioning with IP multicasting. For long distance connections, most of these systems rely on the existence of the Internet multicast backbone - the MBone. However, its generality and complexity is often an obstacle to the establishment and testing of large-scale CVEs. This paper presents the DIVEBONE, an application-level network architecture built as a stand-alone part of the DIVE toolkit [5]. The DIVEBONE is an application-level backbone that can interconnect sub-islands with multicast connectivity and/or single local networks. Furthermore, the DIVEBONE allows for visual analysis of the connection architecture and network traffic and for remote maintenance operations. The DIVEBONE capabilities have been demonstrated and successfully used in a series of large-scale pan-European tests over the Internet, as well as in various experiments involving IP over ISDN and ATM. All trials have proven the qualitative and quantitative adequacy of the DIVEBONE in heterogeneous settings where multicast connectivity in other ways is limited.

Inhabited Television takes traditional broadcast television and combines it with multiuser virtual reality, to give new possibilities for interaction and participation in and around shows or channels. “Out Of This World” was an experimental inhabited TV show, staged in Manchester, in September 1998, using the MASSIVE-2 system. During this event we captured comprehensive records of network traffic, and additional logs of user activity (in particular movement and speaking). In this paper we present the results of our analyses of network and user activity in these shows. We contrast our results with those obtained from previous analyses of teleconferencing-style scenarios. We find that the inhabited television scenario results in much higher levels of user activity, and significant bursts of coordinated activity. We show how these characteristics must be taken into account when designing a system and infrastructure for applications of this kind. In particular, it is clear that any notion of strict turn-taking (and associated assumptions about resource sharing) is completely unfounded in this domain. We also show that the concept of “levels of participation” is a powerful tool for understanding and managing the bandwidth-requirements of an inhabited television event.

In this paper, we describe formations, a means for the explicit support of groups and group effects in Collaborative Virtual Environments (CVEs). Being part of a formation affects a participant's experience of a virtual environment. We introduce a framework that defines the components of a formation, including an object of interest, members, non-members and leaders. We describe how formations may be applied, using the concept of Inhabited TV as a basis.

Collaborative Virtual Environments (CVEs) are shared virtual spaces designed to enhance collaboration between the - usually remote - participants. The deployment of Collaborative Virtual Environments over wide area networks increases typical network delays, potentially breaking the consistency between the replicated versions of an environment at the participants' sites. This paper presents our qualitative observations of an experiment involving two players engaged in a virtual ball game in the presence of increasing network delays. It also describes how network delay affected the participants' behaviour and produced collaboration breakdowns. We observed that, as the network delay increases, the users modify their playing strategies in an attempt to cope with the situation, presenting several types of adaptation strategy. Knowledge of the presence and effect of delays is a major factor in allowing users to adopt strategies for coping with inconsistencies. We propose that if the participants were made more aware of the behaviour of the system, e.g. the presence of delays, then they might be able to improve their performance. Consequently, we propose a number of techniques to increase the user's knowledge of infrastructural characteristics such as delay.

We extend previous work on texture mapping video streams into virtual environments by introducing awareness driven video QoS.This uses movements within a shared virtual world to activate different video services.In turn, these services have different settings for underlying QoS parameters such as frame-rate, resolution and compression.We demonstrate this technique through a combined conferencing!mediaspace application which uses awareness driven video for facial expressions and for views into remote physical environments.We reflect on the issues of spatial consistency, privacy, seamless shifts in mutual involvement and making underlying QoS mechanisms more visible, malleable and flexible.

~s paper explores and evaluates the support for objectfocused cotiaboration provided by a destiop CoUaborative Virtual Environment me system was usd to support an experimental 'design' task.Video recordings of the participants' activities factitated an observationrd analysis of interaction in, and through, the virtual world.Observations include problems due to tigmented views of embodiments in relation to shared objects; participants compensating with spoken accounts of their actions; and difficulties in understanding otiers' perspectives.Design impXcations include: more expficit representations of actions than are provided by pseudo-humanoid embodiments; and navigation techniques that are sensitive to the actions of others.

We propose an approach to creating shared mixed realities based on the construction of transparent boundaries between real and virtual spaces. First, we introduce a taxonomy that classifies current approaches to shared spaces according to the three dimensions of transportation, artificiality, and spatiality. Second, we discuss our experience of staging a poetry performance simultaneously within real and virtual theaters. This demonstrates the complexities involved in establishing social interaction between real and virtual spaces and motivates the development of a systematic approach to mixing realities. Third, we introduce and demonstrate the technique of mixed-reality boundaries as a way of joining real and virtual spaces together in order to address some of these problems.

We introduce a framework for supporting crowds of participants in collaborative virtual environments (CVEs). The framework is realised as an extension to our previous spatial model of interaction and aims to provide greater scaleability and flexibility for communication between the inhabitants of virtual worlds. Our framework introduces an explicit crowd mechanism into CVEs in order to support the formation and activation of different kinds of crowd with different effects on mutual awareness and communication (achieved through the use of aggregation techniques combined with awareness adaptation). We present a demonstration application called the Arena - a shared space for staging on-line performances in front of a live audience. Keywords CSCW, Virtual Reality, Crowds INTRODUCTION Our aim is to introduce and demonstrate a framework for supporting crowds in collaborative virtual environments (CVEs). This framework is intended to support the development of more scaleable CVEs than has bee...

We review current spatial approaches to CSCW (mediaspaces, spatial video conferencing, collaborative virtual environments and telepresence)and classify them along the proposed dimensions of transportation, artificiality and spatiality.This classification leads us to identify new shared space application so called mixed realities.We present an example of a mixed reality called the Internet Foyer, an application which provides a unified entry point into an organisation's physical and electronic environments and which supports awareness and chance encounters between the occupants of physical and synthetic space.

This paper explores the issue of user embodiment within collaborative virtual environments. By user embodiment we mean the provision of users with appropriate body images so as to represent them to others and also to themselves. By collaborative virtual environments we mean multi-user virtual reality systems which explicitly support co-operative work (although we argue that the results of our exploration may also be applied to other kinds of collaborative system). The main part of the paper identifies a list of embodiment design issues including: presence, location, identity, activity, availability, history of activity, viewpoint, actionpoint, gesture, facial expression, voluntary versus involuntary expression, degree of presence, reflecting capabilities, physical properties, active bodies, time and change, manipulating your view of others, representation across multiple media, autonomous and distributed body parts, truthfulness and efficiency. Following this, we show how these issues are reflected in our own DIVE and MASSIVE prototype systems and also show how they can be used to analyse several other existing collaborative systems.

MASSIVE is a distributed virtual reality system. It provides rich facilities to support user interaction and cooperation via text, audio and graphics media and interaction is controlled by a spatial model of interaction. The communications architecture is based on processes communicating via typed connections which have interfaces on both ends and which integrate RPCs, attributes and streams in a common context. A spatial interface trading service, the aura manager, has been developed to support interface trading in a spatial context. The concepts embodied in the aura manager can be useful in other interface trading situations, especially where notions of "space" and "meeting" may be applied.

Abstract We present a virtual reality application called VR‐VIBE which is intended to support the co‐operative browsing and filtering of large document stores. VR‐VIBE extends a visualisation approach proposed in a previous two dimensional system called VIBE into three dimensions, allowing more information to be visualised at one time and supporting more powerful styles of interaction, The essence of VR‐VIBE is that multiple users can explore the results of applying several simultaneous queries to a corpus of documents. By arranging the queries into a spatial framework, the system shows the relative attraction of each document to each query by its spatial position and also shows the absolute relevance of each document to all of the queries. Users may then navigate the space, select individual documents, control the display according to a dynamic relevance threshold and dynamically drag the queries to new positions to see the effect on the document space. Co‐operative browsing is supported by directly embodying users and providing them with the ability to interact over live audio connections and to attach brief textual annotations to individual documents. Finally, we conclude with some initial observations gleaned from our experience of constructing VR‐VIBE and using it in the laboratory setting.

We describe a prototype virtual reality teleconferencing system called MASSIVE which has been developed as part of our on-going research into collaborative virtual environments. This system allows multiple users to communicate using arbitrary combinations of audio, graphics, and text media over local and wide area networks. Communication is controlled by a so-called spatial model of interaction so that one user's perception of another user is sensitive to their relative positions and orientations. The key concept in this spatial model is the (quantitative) awareness which one object has of another. This is controlled by the observing object's focus and the observed object's nimbus , which describe regions of interest and projection, respectively. Each object's aura defines the total region within which it interacts. This is applied independently in each medium. The system (and the spatial model which it implements) is intended to provide a flexible and natural environment for the spatial mediation of conversation. The model also provides a basis for scaling to relatively large numbers of users. Our design goals include supporting heterogeneity, scalability, spatial mediation, balance of power, and multiple concurrent meetings; MASSIVE meets all of these goals. Our initial experiences show the importance of audio in collaborative VR, and they raise issues about field of view for graphical users, speed of navigation, quality of embodiment, varying perceptions of space, and scalability.