As LLM-based Conversational Avatars increasingly act as collaborators in hybrid indoor navigation, understanding how their personality traits influence human-avatar proxemic behavior is becoming crucial. Prior work has largely examined personality effects in static or one-sided interactions such as sitting, standing, or approaching. However, there is a gap in research on how avatar personality and motion-related factors (e.g., walking speed) shape proxemics when both the human and avatar are in motion. To address this, we developed an AR indoor navigation system featuring a Conversational Virtual Avatar (CVA) with three distinct personalities: Dominant, Warm, and Conscientious. The CVA guides users to destinations within the environment. In a between-subjects study (N=27), we found statistically significant effects of avatar personality and walking speed on proxemic behavior. Our work contributes to a broader understanding of the role of personality and walking speed of a CVA on human-avatar proxemic behaviour during navigation.

Emergency departments (EDs) often experience overcrowding, staff shortages, and long waiting times, which put a strain on clinicians and negatively impact patients’ experiences. Although AI is commonly proposed to optimize clinical workflows, the perspectives of patients are often overlooked in AI design. We report on a four-phase study at a university hospital combining preparatory fieldwork, co-creation workshops, design phase, and storyboard-guided interviews. Our findings reveal a misalignment: clinicians framed the contribution of AI around triage efficiency, while patients emphasized reassurance, empathy, and guidance. Addressing both needs, we developed and evaluated a concept of an ephemeral AI companion for the ED waiting area, designed to provide orientation, support reflection, and prepare patients for consultations without substituting human contact. We contribute: empirical evidence of patients’ needs, concerns, and expectations for AI support, design principles for an ephemeral AI companion concept, and findings from a study conducted with patients during their ED waits.

Generative AI (GenAI) image tools are increasingly used in design practice, enabling rapid ideation but offering limited support for refinement tasks such as adjusting layout, scale, or visual attributes. While text prompts and inpainting allow localized edits, they often remain inefficient or ambiguous for precise, in-context, and iterative refinement—motivating the exploration of alternative methods. This work examines how pen-based scribbles and annotations can enhance GenAI image refinement. A formative study with seven professional designers informed a prototype supporting three input modalities: text-only, visual-only, and combined prompting. A within-subjects study with 30 designers and design students compared these modalities across closed- and open-ended tasks, evaluating expressiveness, efficiency, workload, user experience, iteration, and multimodal strategies. Visual prompts improved clarity and speed for spatial edits while reducing workload, whereas text remained effective for semantic and global changes. The combined modality received the highest overall ratings, enabling complementary use, balancing spatial precision with semantic detail, and supporting smoother iteration. Task-specific preferences also emerged: adding new objects often required both modalities, while moving or modifying elements was typically handled through visual input. This work contributes (1) an empirical comparison of multimodal prompting for GenAI refinement, (2) a prototype integrating scribbles and annotations, and (3) insights into designers’ multimodal strategies to inform future GenAI interfaces that better support refinement in GenAI-supported design workflows.

Meaningful interactions positively impact users’ meaning-making and feeling socially and culturally connected with their surroundings. However, creating such interactions is a continuous, complex challenge. We present the Traces in Use design concept supporting interface contextualization for meaningful human–environment interactions in public places. The concept was developed and evaluated in three steps: (I) exploring traces of use characteristics as inspiration for design, (II) introducing the concept definition, its theoretical evaluation, and a supporting framework, and (III) practically evaluating the concept by developing, contextualizing, and testing three interfaces (a lion interface, a drum, and a storyteller) in two empirical field studies (N = 40). The results show that the concept promotes meaningful interaction by supporting users’ feelings of socio-cultural connectedness and meaning-making. With this, our work contributes the Traces in Use design concept, its development, and its methodological application for meaningful human–environment interactions and interface contextualization in public places.

Human-Centered AI prioritizes end-users’ needs like transparency and usability. This is vital for applications that affect people’s everyday lives, such as social assessment tasks in the public sector. This paper discusses our pioneering effort to involve public sector AI users in XAI application design through a co-creative workshop with unemployment consultants from Estonia. The workshop’s objectives were identifying user needs and creating novel XAI interfaces for the used AI system. As a result of our user-centered design approach, consultants were able to develop AI interface prototypes that would support them in creating success stories for their clients by getting detailed feedback and suggestions. We present a discussion on the value of co-creative design methods with end-users working in the public sector to improve AI application design and provide a summary of recommendations for practitioners and researchers working on AI systems in the public sector.

This paper explores (1) the role of metaphors in physical data representations and (2) the concept of tacit data: implicitly known data which are hard to uncover. In a semester course with twenty-three students, five teams explored how to represent self-chosen ‘tacit data’ in a visualisation, haptification, and dynamic physicalisation. Throughout these phases, our notion of tacit data evolved, resulting in a proposed working definition. Moreover, we noticed that metaphors played an increasingly important role. Based on analysis of students’ work and interviews with them, we found that tacit data and physical data representations need metaphors. For haptifications and physicalisations, metaphors help to circumvent limitations, curate data, and communicate to the audience. As tacit data were seen as ‘soft’ and difficult to quantify, metaphors made the data workable. Furthermore, tacit data benefit from physical representations, which offer further dimensions to represent the feeling and intimate aspects of data.

Communication is crucial for interpersonal connection, but sometimes we simply cannot find the right words. Some data, such as complex emotions, are either hard to quantify or are otherwise difficult to communicate. We have access to numerous personal statistics from quantified self devices, but hidden data are either untracked or require abstraction. In this paper, we explore physicalizations to communicate hidden data between couples. We recruited six couples (N=12 participants, 163 telegram responses) to participate in a two-week sensitization diary study followed by two participatory co-design sessions. We then hosted a one-day expert prototyping workshop (N=5) to create tangible artifacts based on the findings of the participatory phase. By iterating on the topic in three ways, we contribute (i) a design framework for understanding and tangibly representing hidden data, (ii) a discussion on the appropriateness of these methodologies, and (iii) open research questions to guide future research in the field.

As previous studies have shown, the environment of creative people can have a significant impact on their creative process and thus on their creations. However, with the advent of digital tools such as virtual instruments and digital audio workstations, more and more creative work is digital and decoupled from the creator’s environment. Virtual Reality technologies open up new possibilities here, as creative tools can seamlessly merge with any virtual environment the user finds himself in. This paper reports on the human-centered design process of a VR application that aims at supporting the user’s individual needs to support their creativity while composing percussive beats in virtual environments. For this purpose, we derived factors that influence creativity from literature and conducted focus group interviews in order to learn how virtual environments and 3DUI can be designed for creativity support. In a subsequent laboratory study, we let users interact with a virtual step sequencer UI in virtual environments that were either customizable or fixed/unchangeable. By analyzing post-test ratings from music experts, self-report questionnaires, and user behavior data, we examined the effects of such customizable virtual environments on user creativity, user experience, flow, and subjective creativity support scales. While we did not observe a significant impact of this independent variable on user creativity, user experience or flow, we found that users had specific individual needs regarding their virtual surroundings and strongly preferred customizable virtual environments, even though the fixed virtual environment was designed to be creatively stimulating. We also observed consistently high flow and user experience ratings, which promote human-centered design of VR-based creativity support tools in a musical context.

Creating social Virtual Environments (VEs) is an ongoing challenge. Traces of prior human interactions, or traces of use, are used in Physical Environments (PEs) to create more meaningful relationships with the PE and the people within it. In this paper, we explore how the concept of traces of use can be transferred from PEs to VEs to increase known success factors for social VEs, such as increased social presence. First, we introduce a conceptualization and discussion ($N=4$ expert interviews) of a "Traces in VEs" framework. Second, we evaluate the framework in two lab studies ($N=46$ in total), exploring the effect of traces in (i) VE vs. PE, and (ii) on social presence. Our findings confirm that traces increase the feeling of social presence. However, their meaning may differ depending on the environment. Our framework offers a structured overview of relevant components and relationships that need to be considered when designing meaningful user experiences in VE using traces. Thus, our work is valuable for practitioners and researchers who systematically want to create social VEs.

With head mounted displays, consumers are able to transition from the real world to virtual realities. However, this requires frequent transitions between the two realities to maintain their physical integrity and awareness of the real world while in the virtual space. We completed two consecutive studies to investigate the dimensions of a system that supports seamless transition between realities without requiring the user to remove the headset. Our results are twofold: First, based on the the analysis of structured interviews (n=20), we present a conceptualization of existing solutions (n=37) and novel ideas (n=9) in the form of a design space. Second, we present the results of a user study (n=36) in which we tested two exemplary prototypes that evolved from the design space, called “Sky Portal” and “Virtual Phone.” Our exploration shows that our “Virtual Phone” metaphor has the potential to support HMD users in completing bidirectional transitions along Milgram's reality-virtuality continuum. Users are also enabled to complete micro-interactions across the realities, even without performance loss.

Maintaining awareness of real world boundaries whilst being immersed in virtual reality (VR) with head mounted displays (HMDs), is a necessity for the physical integrity of the user. This paper explores whether individual human senses can be allocated to the real and the virtual world and what effect this has on workload, presence, performance and perceived safety. We present the results of a lab study ( N=33) where the auditory and haptic sense of participants was trained to be an indicator for real world boundaries, while their visual sense was bound to a VR experience with an HMD. Our results suggests that allocating senses increases workload. However, while performance is comparable to purely visual indications of boundaries, sense allocation seems to improve presence. Participants prefer the signals to be separate or combined subsequently, depending on the priority and proximity to the boundary. This exploratory study is valuable for developers and researchers who want to start including audio and haptic signals as indicators for real world boundaries.

Head-mounted displays (HMDs) are being used for VR and AR applications and increasingly permeate our everyday life. At the same time, a detailed understanding of interruptions in settings where people wearing an HMD (HMD user) and people not wearing an HMD (bystander) is missing. We investigate (a) whether bystanders are capable of identifying when HMD users switch tasks by observing their gestures, and hence exploit opportune moments for interruptions, and (b) which strategies bystanders employ. In a lab study (N=64) we found that bystanders are able to successfully identify both task switches (83%) and tasks (77%) within only a few seconds of the task switch. Furthermore, we identified interruption strategies of bystanders. From our results we derive implications meant to support designers and practitioners in building HMD applications that are used in a co-located collaborative setting.

Immersive Virtual Reality (IVR) is a growing 3D environment, where social and commercial applications will require user authentication. Similarly, smart homes in the real world (RW), offer an opportunity to authenticate in the third dimension. For both environments, there is a gap in understanding which elements of the third dimension can be leveraged to improve usability and security of authentication. In particular, investigating transferability of findings between these environments would help towards understanding how rapid prototyping of authentication concepts can be achieved in this context. We identify key elements from prior research that are promising for authentication in the third dimension. Based on these, we propose a concept in which users' authenticate by selecting a series of 3D objects in a room using a pointer. We created a virtual 3D replica of a real world room, which we leverage to evaluate and compare the factors that impact the usability and security of authentication in IVR and RW. In particular, we investigate the influence of randomized user and object positions, in a series of user studies (N=48). We also evaluate shoulder surfing by real world bystanders for IVR (N=75). Our results show that 3D passwords within our concept are resistant against shoulder surfing attacks. Interactions are faster in RW compared to IVR, yet workload is comparable.

With the adoption of mobile head mounted displays (HMDs) amongst non-experts outside of lab settings, it becomes increasingly important to understand what factors influence a holistic mobile virtual reality (MVR) user experience. We present the results of a field study (N=34), in which we used three methods - a drawing task, a storytelling exercise, and the technology acceptance questionnaire (TAM) - to explore factors, beyond technical capability, that influence the user experience of HMDs. Our analysis (1) highlights factors that designers and researchers can adopt to create and evaluate socially acceptable MVR systems for non-expert users outside a lab context, and (2) puts these factors in context with existing research from industry and academia.

Cutscenes in Virtual Reality (VR) games enhance story telling by delivering output in the form of visual, auditory, or haptic feedback (e.g., using vibrating handheld controllers). Since they lack interaction in the form of user input, cutscenes would significantly benefit from improved feedback. We introduce the concept and implementation of ElectroCutscenes, where Electric Muscle Stimulation (EMS) is leveraged to elicit physical user movements to different body parts to correspond to those of personal avatars in cutscenes of VR games while the user stays passive. Through a user study (N=22) in which users passively received kinesthetic feedback resulting in involuntarily movements, we show that ElectroCutscenes significantly increases perceived presence and realism compared to controller-based vibrotactile and no haptic feedback. Furthermore, we found preliminary evidence that combining visual and EMS feedback can evoke movements that are not actuated by either of them alone. We discuss how to enhance realism and presence of cutscenes in VR games even when EMS can partially rather than completely actuate the desired body movements.

We investigate instructor representations (IRs) in the context of virtual trainings with head mounted displays (HMD). Despite the recently increased industry and research focus on virtual training in immersive virtual reality (IVR), the effect of IRs on the performer (VR user) has received little attention. We present the results of a study (N=33), evaluating the effect of three IRs - webcam, avatar and sound-only - on social presence (SP) and performance (PE) of the VR user during task completion. Our results show that instructor representation has an effect on SP and that, contrary to our assumption based on prior work, it affects performance negatively.