Designing affective behaviors for animal-inspired social robots often relies on intuition and personal experience, leading to fragmented outcomes. To provide more systematic guidance, we first coded and analyzed human–pet interaction videos, validated insights through literature and interviews, and created structured reference cards that map the design space of pet-inspired affective interactions. Building on this, we developed MojiKit, a toolkit combining reference cards, a zoomorphic robot prototype (MomoBot), and a behavior control studio. We evaluated MojiKit in co-creation workshops with 18 participants, finding that MojiKit helped them design 35 affective interaction patterns beyond their own pet experiences, while the code-free studio lowered the technical barrier and enhanced creative agency. Our contributions include the data-informed structured resource for pet-inspired affective HRI design, an integrated toolkit that bridges reference materials with hands-on prototyping, and empirical evidence showing how MojiKit empowers users to systematically create richer, more diverse affective robot behaviors.

Shaking a cup of wine or other fluids in virtual environments is engaging but has been limited by challenges in delivering real-time haptic feedback for liquid collisions. ShakeSense is a haptic rendering system that integrates electrotactile stimulation with physics-based simulation to deliver immersive feedback for liquid dynamics in handheld containers. It employs a high-density electrode array to deliver dynamic tactile sensations, conveying friction and pressure changes on the user’s fingerpad. A dedicated end-to-end pipeline computes fingerpad forces from liquid-container-finger interactions, ensuring feedback aligns with natural fluid movement. Two studies evaluated ShakeSense’s performance and user perception. Study 1 showed that electrotactile patterns were distinguishable across directions, and synchronizing container movement with stimulation enhanced perceived force changes. Study 2 demonstrated that ShakeSense effectively simulated liquid motion, capturing multidimensional, coordinated interactions, and outperformed conventional Center-of-Mass approaches. Overall, ShakeSense provides clear, fine-grained tactile feedback for fluid interactions.

Motion sickness, in addition to its persistent long-term effects, also exhibits short-term effects characterized as transient physiological discomfort, which changes rapidly with variations in locomotion. However, such discomforts are challenging to assess using current subjective scales and objective physiological measurements. To tackle this issue, this paper suggests continuous measurement methods designed specifically for evaluating transient physiological discomfort during VR locomotion. Through a user-elicitation study, three preferred measurement methods—’squeezing ball’, ’sliding thumb’, and ’rubbing thigh’—were identified. These techniques were then evaluated for reliability, validity, attention, presence, and workload, with ’sliding thumb’ identified as the most effective option. The paper expands traditional measurement methods to capture users’ physiological experiences in VR interactions, offering practical choices for researchers in this field along with an in-depth discussion of design considerations, detailed implementation guidelines, and potential ways to optimize the VR experiences utilizing the measurement data.

Grasping objects typically relies on visual input to pre-shape the hand and plan movement trajectories, a process often disrupted in visually impaired (VI) individuals. ElectroGrasp is a wearable electro-tactile system that delivers anticipatory proprioceptive and tactile information through three complementary modalities: Grasping Orientation, Size, and Shape. This system dynamically conveys spatial features-thereby enhancing anticipatory grasp planning and control through tactile perception. Three experiments were conducted to evaluate ElectroGrasp. The first examined tactile pattern discriminability, size perception thresholds, and the reliability of orientation encoding. The second assessed learning time with ElectroGrasp and its effectiveness in supporting spatial representation, demonstrating accurate spatial perception of objects from electrotactile input. The third compared grasp aperture under audio versus electrotactile cues, revealing that ElectroGrasp reduced hand overshoot and regrasp corrections. Overall, the results demonstrate that ElectroGrasp provides efficient tactile information, enables improved anticipatory grasp planning comparable to visual cues, and offers a novel assistive solution for VI users.

Immersive creation tools enhance spatial understanding, yet they push animators to abandon mature 2D desktop practices; Pure desktop setups, however, lack embodied spatial manipulation, making tool switching cognitively costly. To address this issue, We present AniXDim, a cross-dimensional interaction system for 3D character animation that unifies precise planar editing and embodied spatial control without explicit mode toggles. A commodity mouse is augmented for on-demand 6DoF manipulation, and a VR controller is endowed with high-precision planar input through adaptive projection, forming bidirectional dimensional augmentation. Users simply raise or rest the device to enable near-frictionless transitions, while a single autostereoscopic desktop display adapts depth to the inferred interaction state, supporting keyframe, pose, and reference authoring within one consistent workspace. A controlled user study comparing AniXDim with pure desktop and pure VR baselines indicates significant performance gains over the desktop baseline and comparable efficiency to the VR baseline, and higher usability ratings while maintaining comparable workload. These findings suggest that near-frictionless dimensional switching can reconcile 2D precision and 3D embodiment, offering a low-learning-overhead pathway for future hybrid desktop animation pipelines and broader 2D–3D authoring domains.

While virtual reality (VR) enables emotional engagement in cultural heritage (CH) context, its real-time effects on emotional responses throughout the experience and their potential influence on heritage identity remain unexplored. In this study, we present a case of Azheke Village at Hani Rice Terraces in China, co-designing a CH experience in VR with multi-stakeholders, and evaluate how it evokes emotional responses during the whole experience and enhances heritage identity among young local residents and visitors. Our findings reveal that the VR experience effectively evoked emotional responses and enhanced heritage identity across all groups, with changes of emotional arousal showing the strongest relationship with social-value-based heritage identity enhancement among the local residents. This research contributes to human-computer interaction (HCI) and heritage research field by offering empirical findings, which also provides rich design reflections and implications for future research practices to develop interactive experiences to engage young generations in CH inheritance.

This work presents Dual-Stick, a novel controller with two sticks connected at the end that innovates a Dual-Ray interaction paradigm to enrich raycasting input in Virtual Reality (VR). Dual-Stick leverages the inherent human dexterity in using everyday tools such as clamps and tweezers to adjust the relative angle between two sticks. This design supports Dual-Ray interactions that provide with a heuristics-based enhanced mechanism. It also offers more flexible manipulation by taking advantages of additional degrees of freedom provided by clamping angle. We conducted two studies to evaluate the effectiveness of Dual-Ray in target selection and manipulation tasks. The results indicated that Dual-Ray significantly improved efficiency in target selection compared to single-ray input but did not outperform the enhanced single-ray technique. In terms of manipulation, Dual-Ray effectively reduced completion time and mode switching compared to single-ray input.

A safety boundary wall in VR is a virtual barrier that defines a safe area, allowing users to navigate and interact without safety concerns. However, existing implementations neglect to utilize the safety boundary wall's large surface for displaying interactive information. In this work, we propose the BoundaryScreen technique based on the "walking outward" metaphor to add interactivity to the safety boundary wall. Specifically, we augment the safety boundary wall by placing the home screen on it. To summon the home screen, the user only needs to walk outward until it appears. Results showed that (i) participants significantly preferred BoundaryScreen in the outermost two-step-wide ring-shaped section of a circular safety area; and (ii) participants exhibited strong "behavioral inertia" for walking, i.e., after completing a routine activity involving constant walking, participants significantly preferred to use the walking-based BoundaryScreen technique to summon the home screen.

Touch interaction is one of the fundamental interaction paradigms in XR, as users have become very familiar with touch interactions on physical touchscreens. However, users typically need to perform extensive arm movements for engaging with XR user interfaces much larger than mobile device touchscreens. We propose the SummonBrush technique to facilitate easy access to hidden windows while interacting with large XR user interfaces, requiring minimal arm movements. The SummonBrush technique adds a virtual brush to the index fingertip of a user's hand. Upon making contact with a virtual user interface, the brush bends and diverges and ink starts to diffuse in it. The more the brush bends and diverges, the more the ink diffuses. The user can summon hidden windows or background applications in situ, which is achieved by firstly pressing the brush against the user interface to make ink fully fill the brush and then perform swipe gestures. Also, the user can press the brush against the thumbtails of background applications in situ to quickly cycle them through. Ecological studies showed that SummonBrush significantly reduced the arm movement time by 39% and 34% in summoning hidden windows and activating/closing background applications, respectively, leading to a significant decrease in reported physical demand.

This paper presents TacTex, a textile-based interface that provides high-resolution haptic feedback and touch-tracking capabilities. TacTex utilizes electrotactile stimulation, which has traditionally posed challenges due to limitations in textile electrode density and quantity. TacTex overcomes these challenges by employing a multi-layer woven structure that separates conductive weft and warp electrodes with non-conductive yarns. The driving system for TacTex includes a power supply, sensing board, and switch boards to enable spatial and temporal control of electrical stimuli on the textile, while simultaneously monitoring voltage changes. TacTex can stimulate a wide range of haptic effects, including static and dynamic patterns and different sensation qualities, with a resolution of 512 × 512 and based on linear electrodes spaced as closely as 2mm. We evaluate the performance of the interface with user studies and demonstrate the potential applications of TacTex interfaces in everyday textiles for adding haptic feedback.

Multi-user locomotion in VR has grown increasingly common, posing numerous challenges. A key factor contributing to these challenges is the gaps in experience between active and passive users during co-locomotion. Yet, there remains a limited understanding of how and to what extent these experiential gaps manifest in diverse multi-user co-locomotion scenarios. This paper systematically explores the gaps in physiological and psychological experience indicators between active and passive users across various locomotion situations. Such situations include when active users walk, fly by joystick, or teleport, and passive users stand still or look around. We also assess the impact of factors such as sub-locomotion type, speed/teleport-interval, motion sickness susceptibility, etc. Accordingly, we delineate acceptability disparities between active and passive users, offering insights into leveraging notable experimental findings to mitigate discomfort during co-locomotion through avoidance or intervention.

Sketching in Virtual Reality (VR) is challenging mainly due to the absence of physical surface support and virtual depth perception cues, which induce high cognitive and sensorimotor load. This paper presents WieldingCanvas, an interactive VR sketching platform that integrates canvas manipulations to draw lines and curves in 3D. Informed by real-life examples of two-handed creative activities, WieldingCanvas interprets users’ spatial gestures to move, swing, rotate, transform, or fold a virtual canvas, whereby users simply draw primitive strokes on the canvas, which are turned into finer and more sophisticated shapes via the manipulation of the canvas. We evaluated the capability and user experience of WieldingCanvas with two studies where participants were asked to sketch target shapes. A set of freehand sketches of high aesthetic qualities were created, and the results demonstrated that WieldingCanvas can assist users with creating 3D sketches.

Virtual reality (VR) is found to present significant cognitive challenges due to its immersive nature and frequent sensory conflicts. This study systematically investigates the impact of sensory conflicts induced by VR remapping techniques on cognitive fatigue, and unveils their correlation. We utilized three remapping methods (haptic repositioning, head-turning redirection, and giant resizing) to create different types of sensory conflicts, and measured perceptual thresholds to induce various intensities of the conflicts. Through experiments involving cognitive tasks along with subjective and physiological measures, we found that all three remapping methods influenced the onset and severity of cognitive fatigue, with visual-vestibular conflict having the greatest impact. Interestingly, visual-experiential/memory conflict showed a mitigating effect on cognitive fatigue, emphasizing the role of novel sensory experiences. This study contributes to a deeper understanding of cognitive fatigue under sensory conflicts and provides insights for designing VR experiences that align better with human perceptual and cognitive capabilities.

Typing in mid-air is often perceived as intuitive yet presents challenges due to finger coactivation, a neuromechanical phenomenon that involves involuntary finger movements stemming from the lack of physical constraints. Previous studies were used to examine and address the impacts of finger coactivation using algorithmic approaches. Alternatively, this paper explores the neuromechanical effects of finger coactivation on mid-air typing, aiming to deepen our understanding and provide valuable insights to improve these interactions. We utilized a wearable device that restrains finger coactivation as a prop to conduct two mid-air studies, including a rapid finger-tapping task and a ten-finger typing task. The results revealed that restraining coactivation not only reduced mispresses, which is a classic coactivated error always considered as harm caused by coactivation. Unexpectedly, the reduction of motor control errors and spelling errors, thinking as non-coactivated errors, also be observed. Additionally, the study evaluated the neural resources involved in motor execution using functional Near Infrared Spectroscopy (fNIRS), which tracked cortical arousal during mid-air typing. The findings demonstrated decreased activation in the primary motor cortex of the left hemisphere when coactivation was restrained, suggesting a diminished motor execution load. This reduction suggests that a portion of neural resources is conserved, which also potentially aligns with perceived lower mental workload and decreased frustration levels.

Spatial search tasks are common and crucial in many Virtual Reality (VR) applications. Traditional methods to enhance the performance of spatial search often employ sensory cues such as visual, auditory, or haptic feedback. However, the design and use of bimanual haptic feedback with two VR controllers for spatial search in VR remains largely unexplored. In this work, we explored bimanual haptic feedback with various combinations of haptic properties, where four types of bimanual haptic feedback were designed, for spatial search tasks in VR. Two experiments were designed to evaluate the effectiveness of bimanual haptic feedback on spatial direction guidance and search in VR. The results from the first experiment reveal that our proposed bimanual haptic schemes significantly enhanced the recognition of spatial directions in terms of accuracy and speed compared to spatial audio feedback. The second experiment's findings suggest that the performance of bimanual haptic feedback was comparable to or even better than the visual arrow, especially in reducing the angle of head movement and enhancing searching targets behind the participants, which was supported by subjective feedback as well. Based on these findings, we have derived a set of design recommendations for spatial search using bimanual haptic feedback in VR.

The sense of touch plays a crucial role in interactive behavior within virtual spaces, particularly when visual attention is absent. Although haptic feedback has been widely used to compensate for the lack of visual cues, the use of tactile information as a predictive feedforward cue to guide hand movements remains unexplored and lacks theoretical understanding. This study introduces a fingertip aero-haptic rendering method to investigate its effectiveness in directing hand movements during eyes-free spatial interactions. The wearable device incorporates a multichannel micro-airflow chamber to deliver adjustable tactile effects on the fingertips. The first study verified that tactile directional feedforward cues significantly improve user capabilities in eyes-free target acquisition and that users rely heavily on haptic indications rather than spatial memory to control their hands. A subsequent study examined the impact of enriched tactile feedforward cues on assisting users in determining precise target positions during eyes-free interactions, and assessed the required learning efforts. The haptic feedforward effect holds great practical promise in eyeless design for virtual reality. We aim to integrate cognitive models and tactile feedforward cues in the future, and apply richer tactile feedforward information to alleviate users' perceptual deficiencies.

Being able to analyze and derive insights from data, which we call Daily Data Analysis (DDA), is an increasingly important skill in everyday life. While the accessibility community has explored ways to make data more accessible to blind and low-vision (BLV) people, little is known about how BLV people perform DDA. Knowing BLV people’s strategies and challenges in DDA would allow the community to make DDA more accessible to them. Toward this goal, we conducted a mixed-methods study of interviews and think-aloud sessions with BLV people (N=16). Our study revealed five key approaches for DDA (i.e., overview obtaining, column comparison, key statistics identification, note-taking, and data validation) and the associated challenges. We discussed the implications of our findings and highlighted potential directions to make DDA more accessible for BLV people.

Using VR in reclining & lying positions is getting common for users, but upward views caused by posture have to be redirected to be parallel to the ground as when users are standing. This affects users’ locomotion performances in VR due to potential physical restrictions, and the visual-vestibular-proprioceptive conflict. This paper is among the first to investigate the suited locomotion methods and how reclining & lying positions and redirection affect them in such conditions. A user-elicitation study was carried out to construct a set of locomotion methods based on users’ preferences when they were in different reclining & lying positions. A second study developed user-preferred ’tapping’ and ’chair rotating’ gestures, by evaluating their performances at various body reclining angles, we measured the general impacts of posture and redirection. The results showed that these methods worked effectively, but exposed some shortcomings, and users performed worst at 45° reclining angles. Finally, four upgraded methods were designed and verified to improve the locomotion performances.

As electronic textiles have become more advanced in sensing, actuating, and manufacturing, incorporating smartness into fabrics has become of special interest to ubiquitous computing and interaction researchers and designers. However, innovating smart textile interfaces for numerous input and output modalities usually requires expert-level knowledge of specific materials, fabrication, and protocols. This paper presents EmTex, a construction kit based on embroidered textiles, patterned with dedicated sensing, actuating, and connecting components to facilitate the design and prototyping of smart textile interfaces. With machine embroidery, EmTex is compatible with a wide range of threads and underlay fabrics, proficient in various stitches to control the electric parameters, and capable of integrating versatile and reliable interaction functionalities with aesthetic patterns and precise designs. EmTex consists of 28 textile-based sensors, actuators, connectors, and displays, presented with standardized visual and tactile effects. Along with a visual programming tool, EmTex enables the prototyping of everyday textile interfaces for diverse life-living scenarios, that embody their touch input, and visual and haptic output properties. With EmTex, we conducted a workshop and invited 25 designers and makers to create freeform textile interfaces. Our findings revealed that EmTex helped the participants explore novel interaction opportunities with various smart textile prototypes. We also identified challenges EmTex shall face for practical use in promoting the design innovation of smart textiles.

Recent research proposed eyelid gestures for people with upper-body motor impairments (UMI) to interact with smartphones without finger touch. However, such eyelid gestures were designed by researchers. It remains unknown what eyelid gestures people with UMI would want and be able to perform. Moreover, other above-the-neck body parts (e.g., mouth, head) could be used to form more gestures. We conducted a user study in which 17 people with UMI designed above-the-neck gestures for 26 common commands on smartphones. We collected a total of 442 user-defined gestures involving the eyes, the mouth, and the head. Participants were more likely to make gestures with their eyes and preferred gestures that were simple, easy-to-remember, and less likely to draw attention from others. We further conducted a survey (N=24) to validate the usability and acceptance of these user-defined gestures. Results show that user-defined gestures were acceptable to both people with and without motor impairments.

As touch interactions become ubiquitous in the field of human computer interactions, it is critical to enrich haptic feedback to improve efficiency, accuracy, and immersive experiences. This paper presents HapTag, a thin and flexible actuator to support the integration of push button tactile renderings to daily soft surfaces. Specifically, HapTag works under the principle of hydraulically amplified electroactive actuator (HASEL) while being optimized by embedding a pressure sensing layer, and being activated with a dedicated voltage appliance in response to users’ input actions, resulting in fast response time, controllable and expressive push-button tactile rendering capabilities. HapTag is in a compact formfactor and can be attached, integrated, or embedded on various soft surfaces like cloth, leather, and rubber. Three common push button tactile patterns were adopted and implemented with HapTag. We validated the feasibility and expressiveness of HapTag by demonstrating a series of innovative applications under different circumstances.

When users use Virtual Reality (VR) in nontraditional postures, such as while reclining or lying in relaxed positions, their views lean upwards and need to be corrected, to make sure they see upright contents and perceive the interactions as if they were standing. Such upright redirection is excepted to cause visual-vestibular-proprioceptive conflict, affecting users’ internal perceptions (e.g., body ownership, presence, simulator sickness) and external perceptions (e.g., egocentric space perception) in VR. Different body reclining angles may affect vestibular sensitivity and lead to the dynamic weighting of multi-sensory signals in the sensory integration. In the paper, we investigated the impact of upright redirection on users’ perceptions, with users’ physical bodies tilted at various angles backward and views upright redirected accordingly. The results showed that upright redirection led to simulator sickness, confused self-awareness, weak upright illusion, and increased space perception deviations to various extents when users are at different reclining positions, and the situations were the worst at the 45° conditions. Based on these results, we designed some illusion-based and sensory-based methods, that were shown effective in reducing the impact of sensory conflict through preliminary evaluations.

Interacting with out of reach or occluded VR objects can be cumbersome. Although users can change their position and orientation, such as via teleporting, to help observe and select, doing so frequently may cause loss of spatial orientation or motion sickness. We present vMirror, an interactive widget leveraging reflection of mirrors to observe and select distant or occluded objects. We first designed interaction techniques for placing mirrors and interacting with objects through mirrors. We then conducted a formative study to explore a semi-automated mirror placement method with manual adjustments. Next, we conducted a target-selection experiment to measure the effect of the mirror’s orientation on users’ performance. Results showed that vMirror can be as efficient as direct target selection for most mirror orientations. We further compared vMirror with teleport technique in a virtual treasure hunt game and measured participants’ task performance and subjective experiences. Finally, we discuss vMirorr user experience and present future directions.

In this paper, we propose a reconfigurable electrode, RElectrode, using a microfluidic technique that can change the geometry and material properties of the electrode to satisfy the needs for sensing a variety of different types of user input through touch/touchless gestures, pressure, temperature, and distinguish between different types of objects or liquids. Unlike the existing approaches, which depend on the specific-shaped electrode for particular sensing (e.g., coil for inductive sensing), RElectrode enables capacity, inductance, resistance/pressure, temperature, pH sensings all in a single package. We demonstrate the design and fabrication of the microfluidic structure of our RElectrode, evaluate its sensing performance through several studies, and provide some unique applications. RElectrode demonstrates technical feasibility and application values of integrating physical and biochemical properties of microfluidics into novel sensing interfaces.

In this paper, we present HoloBoard, an interactive large-format pseduo-holographic display system for lecture based classes. With its unique properties of immersive visual display and transparent screen, we designed and implemented a rich set of novel interaction techniques like immersive presentation, role-play, and lecturing behind the scene that are potentially valuable for lecturing in class. We conducted a controlled experimental study to compare a HoloBoard class with a normal class through measuring students’ learning outcomes and three dimensions of engagement (i.e., behavioral, emotional, and cognitive engagement). We used pre-/post- knowledge tests and multimodal learning analytics to measure students’ learning outcomes and learning experiences. Results indicated that the lecture-based class utilizing HoloBoard lead to slightly better learning outcomes and a significantly higher level of student engagement. Given the results, we discussed the impact of HoloBoard as an immersive media in the classroom setting and suggest several design implications for deploying HoloBoard in immersive teaching practices.

On-skin haptic interfaces using soft elastomers which are thin and flexible have significantly improved in recent years. Many are focused on vibrotactile feedback that requires complicated parameter tuning. Another approach is based on mechanical forces created via piezoelectric devices and other methods for non-vibratory haptic sensations like stretching, twisting. These are often bulky with electronic components and associated drivers are complicated with limited control of timing and precision. This paper proposes HapBead, a new on-skin haptic interface that is capable of rendering vibration like tactile feedback using microfluidics. HapBead leverages a microfluidic channel to precisely and agilely oscillate a small bead via liquid flow, which then generates various motion patterns in channel that creates highly tunable haptic sensations on skin. We developed a proof-of-concept design to implement thin, flexible and easily affordable HapBead platform, and verified its haptic rendering capabilities via attaching it to users' fingertips. A study was carried out and confirmed that participants could accurately tell six different haptic patterns rendered by HapBead. HapBead enables new wearable display applications with multiple integrated functionalities such as on-skin haptic doodles, visuo-haptic displays and haptic illusions.

Providing users with rich sensations is beneficial to enhance their immersion in Virtual Reality (VR) environments. Wetness is one such imperative sensation that affects users' sense of comfort and helps users adjust grip force when interacting with objects. Researchers have recently begun to explore ways to create wetness illusions, primarily on a user's face or body skin. In this work, we extended this line of research by creating wetness illusion on users' fingertips. We first conducted a user study to understand the effect of thermal and tactile feedback on users' perceived wetness sensation. Informed by the findings, we designed and evaluated a prototype---Mouillé---that provides various levels of wetness illusions on fingertips for both hard and soft items when users squeeze, lift, or scratch it. Study results indicated that users were able to feel wetness with different levels of temperature changes and they were able to distinguish three levels of wetness for simulated VR objects. We further presented applications that simulated an ice cube, an iced cola bottle, and a wet sponge, etc, to demonstrate its use in VR.

The use of Virtual Reality (VR) in applications such as data analysis, artistic creation, and clinical settings requires high precision input. However, the current design of handheld controllers, where wrist rotation is the primary input approach, does not exploit the human fingers' capability for dexterous movements for high precision pointing and selection. To address this issue, we investigated the characteristics and potential of using a pen as a VR input device. We conducted two studies. The first examined which pen grip allowed the largest range of motion---we found a tripod grip at the rear end of the shaft met this criterion. The second study investigated target selection via 'poking' and ray-casting, where we found the pen grip outperformed the traditional wrist-based input in both cases. Finally, we demonstrate potential applications enabled by VR pen input and grip postures.

Most intervention methods used for social skills training in children with autism are dedicated to high-functioning autism (HFA). However, extensive neurological and developmental disorders of low-functioning autism (LFA) have hampered their adoption. In this study, we observed and interviewed children with LFA, and their teachers, from a local educational institution, to better understand the children's social needs and barriers. Then, with the aim of aiding the children with their social activities, we illustrate the design process of SqueeBall, an interactive playground equipment. We evaluated the design with 18 children (16 with LFA and 2 with HFA) between 2.5 and 7 years of age. Results showed that these children had a pleasant game experience when the group bonded, and the equipment had a positive effect on aiding them in various ways. Finally, we discuss the challenges and opportunities of multimedia interaction techniques in aiding children with LFA.

Haptic simulation of hand tools like wrenches, pliers, scissors and syringes are beneficial for finely detailed skill training in VR, but designing for numerous hand tools usually requires an expert-level knowledge of specific mechanism and protocol. This paper presents HapLinkage, a prototyping framework based on linkage mechanism, that provides typical motion templates and haptic renderers to facilitate proxy design of virtual hand tools. The mechanical structures can be easily modified, for example, to scale the size, or to change the range of motion by selectively changing linkage lengths. Resistant, stop, release, and restoration force feedback are generated by an actuating module as part of the structure. Additional vibration feedback can be generated with a linear actuator. HapLinkage enables easy and quick prototypting of hand tools for diverse VR scenarios, that embody both of their kinetic and haptic properties. Based on interviews with expert designers, it was confirmed that HapLinkage is expressive in designing haptic proxy of hand tools to enhance VR experiences. It also identified potentials and future development of the framework.

Intensive exploration and navigation of hierarchical lists on smartphones can be tedious and time-consuming as it often requires users to frequently switch between multiple views. To overcome this limitation, we present PinchList, a novel interaction design that leverages pinch gestures to support seamless exploration of multi-level list items in hierarchical views. With PinchList, sub-lists are accessed with a pinch-out gesture whereas a pinch-in gesture navigates back to the previous level. Additionally, pinch and flick gestures are used to navigate lists consisting of more than two levels. We conduct a user study to refine the design parameters of PinchList such as a suitable item size, and quantitatively evaluate the target acquisition performance using pinch-in/out gestures in both scrolling and non-scrolling conditions. In a second study, we compare the performance of PinchList in a hierarchal navigation task with two commonly used touch interfaces for list browsing: pagination and expand-and-collapse interfaces. The results reveal that PinchList is significantly faster than other two interfaces in accessing items located in hierarchical list views. Finally, we demonstrate that PinchList enables a host of novel applications in list-based interaction?

Selecting an item of interest on smartwatches can be tedious and time-consuming as it involves a series of swipe and tap actions. We present PageFlip, a novel method that combines into a single action multiple touch operations such as command invocation and value selection for efficient interaction on smartwatches. PageFlip operates with a page flip gesture that starts by dragging the UI from a corner of the device. We first design PageFlip by examining its key design factors such as corners, drag directions and drag distances. We next compare PageFlip to a functionally equivalent radial menu and a standard swipe and tap method. Results reveal that PageFlip improves efficiency for both discrete and continuous selection tasks. Finally, we demonstrate novel smartwatch interaction opportunities and a set of applications that can benefit from PageFlip.

Current haptic devices are often bulky and rigid, making them unsuitable for ubiquitous interaction and scenarios where the user must also interact with the real world. To address this gap, we propose HydroRing, an unobtrusive, finger-worn device that can provide the tactile sensations of pressure, vibration, and temperature on the fingertip, enabling mixed-reality haptic interactions. Different from previous explorations, HydroRing in active mode delivers sensations using liquid travelling through a thin, flexible latex tube worn across the fingerpad, and has minimal impact on a user's dexterity and their perception of stimuli in passive mode. Two studies evaluated participants' ability to perceive and recognize sensations generated by the device, as well as their ability to perceive physical stimuli while wearing the device. We conclude by exploring several applications leveraging this mixed-reality haptics approach.

We propose the concept of a guiding system specifically designed for semaphoric gaze gestures, i.e. gestures defining a vocabulary to trigger commands via the gaze modality. Our design exploration considers fundamental gaze gesture phases: Exploration, Guidance, and Return. A first experiment reveals that Guidance with dynamic elements moving along 2D paths is efficient and resistant to visual complexity. A second experiment reveals that a Rapid Serial Visual Presentation of command names during Exploration allows for more than 30% faster command retrievals than a standard visual search. To resume the task where the guide was triggered, labels moving from the outward extremity of 2D paths toward the guide center leads to efficient and accurate origin retrieval during the Return phase. We evaluate our resulting Gaze Gesture Guiding system, G3, for interacting with distant objects in an office environment using a head-mounted display. Users report positively on their experience with both semaphoric gaze gestures and G3.

Smart rings have a unique form factor suitable for many applications, however, they offer little opportunity to provide the user with natural output. We propose passive kinesthetic force feedback as a novel output method for rotational input on smart rings. With this new output channel, friction force profiles can be designed, programmed, and felt by a user when they rotate the ring. This modality enables new interactions for ring form factors. We demonstrate the potential of this new haptic output method though Frictio, a prototype smart ring. In a controlled experiment, we determined the recognizability of six force profiles, including Hard Stop, Ramp-Up, Ramp-Down, Resistant Force, Bump, and No Force. The results showed that participants could distinguish between the force profiles with 94% accuracy. We conclude by presenting a set of novel interaction techniques that Frictio enables, and discuss insights and directions for future research.

We present SoundCraft, a smartwatch prototype embedded with a microphone array, that localizes angularly, in azimuth and elevation, acoustic signatures: non-vocal acoustics that are produced using our hands. Acoustic signatures are common in our daily lives, such as when snapping or rubbing our fingers, tapping on objects or even when using an auxiliary object to generate the sound. We demonstrate that we can capture and leverage the spatial location of such naturally occurring acoustics using our prototype. We describe our algorithm, which we adopt from the MUltiple SIgnal Classification (MUSIC) technique [31], that enables robust localization and classification of the acoustics when the microphones are required to be placed at close proximity. SoundCraft enables a rich set of spatial interaction techniques, including quick access to smartwatch content, rapid command invocation, in-situ sketching, and also multi-user around device interaction. Via a series of user studies, we validate SoundCraft's localization and classification capabilities in non-noisy and noisy environments.

Heart rate monitoring is widely used in clinical care, fitness training, and stress management. However, tracking individuals' heart rates faces two major challenges, namely equipment availability and user motivation. In this paper, we present a novel technique, LivePulse Games (LPG), to measure users' heart rates in real time by having them play games on unmodified mobile phones. With LPG, the heart rate is calculated by detecting changes in transparency of users' fingertips via the built-in camera of a mobile device. More importantly, LPG integrate users' camera lens covering actions as an essential control mechanism in game play, and detect heart rates implicitly from intermittent lens covering actions. We explore the design space and trade-offs of LPG through three rounds of iterative design. In a 12-subject user study, we found that LPG are fun to play and can measure heart rates accurately. We also report the insights for balancing measurement speed, accuracy, and entertainment value in LPG.

We present LensGesture, a pure software approach for augmenting mobile interactions with back-of-device finger gestures. LensGesture detects full and partial occlusion as well as the dynamic swiping of fingers on the camera lens by analyzing image sequences captured by the built-in camera in real time. We report the feasibility and implementation of LensGesture as well as newly supported interactions. Through offline benchmarking and a 16-subject user study, we found that 1) LensGesture is easy to learn, intuitive to use, and can serve as an effective supplemental input channel for today's smartphones; 2) LensGesture can be detected reliably in real time; 3) LensGesture based target acquisition conforms to Fitts' Law and the information transmission rate is 0.53 bits/sec; and 4) LensGesture applications can improve the usability and the performance of existing mobile interfaces.

BodyAvatar is a Kinect-based interactive system that allows users without professional skills to create freeform 3D avatars using body gestures. Unlike existing gesture-based 3D modeling tools, BodyAvatar centers around a first-person "you're the avatar" metaphor, where the user treats their own body as a physical proxy of the virtual avatar. Based on an intuitive body-centric mapping, the user performs gestures to their own body as if wanting to modify it, which in turn results in corresponding modifications to the avatar. BodyAvatar provides an intuitive, immersive, and playful creation experience for the user. We present a formative study that leads to the design of BodyAvatar, the system's interactions and underlying algorithms, and results from initial user trials.

Foot-based gestures have recently received attention as an alternative interaction mechanism in situations where the hands are pre-occupied or unavailable. This paper investigates suitable real-world mappings of foot gestures to invoke commands and interact with virtual workspaces. Our first study identified user preferences for mapping common mobile-device commands to gestures. We distinguish these gestures in terms of discrete and continuous command input. While discrete foot-based input has relatively few parameters to control, continuous input requires careful design considerations on how the user's input can be mapped to a control parameter (e.g. the volume knob of the media player). We investigate this issue further through three user-studies. Our results show that rate-based techniques are significantly faster, more accurate and result if far fewer target crossings compared to displacement-based interaction. We discuss these findings and identify design recommendations.

In this paper we describe the use of kick gestures for interaction with mobile devices. Kicking is a well-st udied leg action that can be harnessed in mobile contexts where the hands are busy or too dirty to interact with the phone. In this paper we examine the design space of kicki ng as an interaction technique through two user studies. The first study investigated how well users were able to control the direction of their kicks. Users were able to aim their kicks best when the movement range is divided into segments of at least 24°. In the second study we looked at the velocity of a kick. We found that the users are able to kick with at least two varying velocities. However, they also often undershoot the target velocity. Finally, we propose some specific applications in which kicks can prove beneficial.