Touch is valued for supporting emotional bonds. How can people access its warmth and nuance remotely, when tech-mediated proxies are so different from direct touch? We assessed the viability of haptic animations as affect-embedded tactile messages, highlighting findings which demonstrate how crucial relationship and shared history is in influencing these expressions in design and interpretation. To investigate haptic messaging, we first identified a set of 10 common emotion-imbued scenarios by surveying 201 people in distance relationships. Then, using a novel prototype of a wearable spatial vibrotactile display, 10 intimate dyads designed 167 haptic encodings matching the provided scenarios plus 17 user-defined “wildcards”. A week later, 21 individuals interpreted sentiment from encodings designed by themselves, a partner or a stranger. We examined design strategies, engagement, and compared humanversusmachine interpretation accuracy. A striking finding was participants’ facile use of shared context when it was available, building on “inside stories” to communicate subtle meanings with high effectiveness despite the unfamiliar medium, and doing so with evident fun. We analyze recognition accuracy and share insights on what it might take to make interpersonal haptic messaging work.

The energy consumption of mobile network infrastructures has been witnessed to rise significantly in recent years due to the massive growth of mobile traffic triggered by the increasing adoption of 5G networks and massive applications of the Internet of Things (IoT). The increase in network traffic not only demands network densification but also increases the operational expenditure (OPEX) of the mobile network operators as well as the environmental and sustainability concerns. To address such a challenge, green energy technology has received increasing attention. However, keeping the density of small cell base stations (SCBSs) and matching the dynamics of available energy variations to the user service request arrivals are non-trivial that need further investigation. This paper proposes to utilize the microgeneration of renewable energy (RE) infrastructure with traffic-aware load offloading integrated with advanced sleep mode (ASM) operation. The centralized renewable energy microgeneration approach is adopted to power the high density of SCBSs installed at a dispersed geographical location. The stochastic modeling-based traffic offloading can offload the macro base station (MBS) users to SCBSs depending on the traffic intensity. The advanced sleep mode stochastic model is presented to gradually manage the underutilized SCBSs into sleep modes based on the traffic load. The proposed scheme is developed to reduce the on-grid energy consumption whilst meeting the quality of service (QoS) requirement in terms of blocking probability and reactivation delay. The numerical results demonstrated that the proposed solution can achieve a significant amount of energy-saving depending upon the renewable energy availability and MBS traffic offloading with ASMs policies.

A massive number of small cell base stations are expected to be deployed in the 5G and beyond 5G mobile communication networks due to the exponential increase in mobile traffic. This will directly lead to not only a significant increase in energy consumption but also the overall operational cost and carbon footprint. An energy provision based on renewable energy generation to power these small cell base stations is considered a sustainable and promising solution to address this challenge. This paper exploits the cost-effective and low-carbon energy provision solution for individual small-cell mobile networks and presents two different potential frameworks, i.e., centralized and distributed energy provision, respectively. The former supplies nearby small cell base stations through a centralized renewable energy source with energy storage facilities. For the latter, small cell base stations can be supplied by utilizing local renewable energy and storage facilities. These two frameworks are assessed and compared in terms of renewable energy utilization and carbon emission reduction in the presence of time-varying traffic loads, small cell locations and renewable energy availabilities. In addition, we devise energy management for these configurations by incorporating a resource-on-demand strategy in the proposed framework. The numerical simulation results demonstrate that the proposed centralized renewable energy generation strategy for nearby small cells maximizes the cost and energy efficiencies of the network.

We present a compact broadband linear actuator, Chasm, that renders expressive haptic feedback on wearable and handheld devices. Unlike typical motor-based haptic devices with integrated gearheads, Chasm utilizes a miniature leadscrew coupled to a motor shaft, thereby directly translating the high-speed rotation of the motor to the linear motion of a nut carriage without an additional transmission. Due to this simplicity, Chasm can render low-frequency skin-stretch and high-frequency vibrations, simultaneously and independently. We present the design of the actuator assembly and validate its electromechanical and perceptual performance. We then explore use cases and show design solutions for embedding Chasm in device prototypes. Finally, we report investigations with Chasm in two VR embodiments, i.e., in a headgear band to induce locomotion cues and in a handheld pointer to enhance dynamic manual interactions. Our explorations show wide use for Chasm in enhancing user interactions and experience in virtual and augmented settings.

Recent studies have shown that decomposing spoken or written language into phonemes and transcribing each phoneme into a unique vibrotactile pattern enables people to receive lexical messages on the arm. A potential barrier to adopting this new communication system is the time and effort required to learn the association between phonemes and vibrotactile patterns. Therefore, in this study, we compared the learnability and generalizability of different learning approaches, including guided learning, self-guided learning, and a mnemonic device. We found that after 65 minutes of learning spread across 3 days, 67% of participants, including both native and non-native English speakers, following the guided learning could identify 100 haptic words with over 90% accuracy, while only 20% of participants using the self-guided learning paradigm could do so.

We present a study to examine one's learning and processing capacity of broadband tactile information, such as that derived from speech. In Study 1, we tested a user's capability to recognize tactile locations and movements on the forearm in the presence of masking stimuli and determined 9 distinguishable tactile symbols. We associated these symbols to 9 phonemes using two approaches, random and articulation associations. Study 2 showed that novice participants can learn both associations. However, performance for retention, construction of words and knowledge transfer to recognize unlearned words was better with articulation association. In study 3, we trained novel participants to directly recognize words before learning phonemes. Our results show that novel users can retain and generalize the knowledge to recognize new words faster when they were directly train on words. Finally, Study 4 examined optimal presentation rate for the tactile symbols without compromising learning and recognition rate.

In our daily lives, we rely heavily on our visual and auditory channels to receive information from others. In the case of impairment, or when large amounts of information are already transmitted visually or aurally, alternative methods of communication are needed. A haptic language offers the potential to provide information to a user when visual and auditory channels are unavailable. Previously created haptic languages include deconstructing acoustic signals into features and displaying them through a haptic device, and haptic adaptations of Braille or Morse code; however, these approaches are unintuitive, slow at presenting language, or require a large surface area. We propose using a multi-sensory haptic device called MISSIVE, which can be worn on the upper arm and is capable of producing brief cues, sufficient in quantity to encode the full English phoneme set. We evaluated our approach by teaching subjects a subset of 23 phonemes, and demonstrated an 86% accuracy in a 50 word identification task after 100 minutes of training.

Apparent tactile motion has been shown to occur across many contiguous part of the body, such as fingers, forearms, and back. A recent study demonstrated the possibility of eliciting the illusion of movement from one hand to the other when interconnected by a tablet. In this paper we explore intermanual apparent tactile motion without any object between them. In a series of psychophysical experiments we determine the control space for generating smooth and consistent motion, using two vibrating handles which we refer to as the Hand-to-Hand vibrotactile device. In a first experiment we investigated the occurrence of the phenomenon (i.e., movement illusion) and the generation of a perceptive model. In a second experiment, based on those results, we investigated the effect of hand postures on the illusion. Finally, in a third experiment we explored two visuo-tactile matching tasks in a multimodal VR setting. Our results can be applied in VR applications with intermanual tactile interactions.

Our hands-on studio will explore how to create meaningful haptic interactions that engage different areas of the body. Participants will gain an understanding of apparent tactile illusions, a perception of illusory motion between two areas on the body, and apply this knowledge towards generating their own haptic experiences. We will introduce participants to Stereo Haptics, a toolkit used to quickly generate haptic sensations through audio platforms with off the shelf hardware and open source software. The studio begins with an introduction to haptics, haptic technology and the illusions it can help create. Next, participants will begin experimenting with Stereo Haptics and using the toolkit to create dynamic haptic interactions. In the final section, participants will work in groups to design haptic solutions for real-life scenarios. By the end of the studio, participants will have a good understanding of tactile illusions, how to create them, and how they can be applied to enrich tangible and embodied interaction using simple stereo-sound technologies.

We present a VR360° video player with haptic feedback playback. The VR360HD application enhances VR viewing experience by triggering customized haptic effects associated with user's activities, biofeedback, network messages and customizable timeline triggers incorporated in the VR media. The app is developed in the Unity3D game engine and tested using a GearVR headset, therefore allowing users to add animations to VR gameplay and to the VR360° streams. A custom haptic plugin allows users to author and associate animated haptic effects to the triggers, and playback these effects on a custom haptic hardware, the Haptic Chair. We show that the VR360HD app creates rich tactile effects and can be easily adapted to other media types.

Research on children's cognitive development has demonstrated the positive effects of listening to stories. However, traditional story listening is losing its appeal to other entertainment technology such as video games. Hence, there is growing interest in studying the influence of ancillary media such as sound and interactive effects, although haptic sensory input has remained relatively unexploited. We implemented a haptic vest that generates vibrotactile stimulation related to story content to augment story listening. Study 1 showed that 5- and 6-year olds, but not 4-year olds, could associate haptic effects with semantic interpretations. In Study 2, children listened to stories containing elements with or without haptic effects. The 5- and 6-year olds showed better comprehension of the haptically-signaled content in the higher-performance story. The results provide initial evidence that haptic effects can potentially enhance the reading/listening experience of children beyond 4 years.

Engaging children with traditional approaches in education, especially reading, grows ever more difficult in the face of their attachment to tablets and computer games. We explore the possibility of making the story reading experience more interesting and memorable for children using haptic augmentation. In this paper, we present FeelSleeve, an interface that allows children to feel story events in their hands while they are reading on a mobile device. FeelSleeve uses transducers and audio output from the tablet within a gloved attachment to create vibratory effects that are meaningfully related to story content. We describe a study investigating whether embedding such haptic feedback into stories enhances reading for six to nine year olds. Our results indicate that story events accompanied by haptic feedback are better comprehended and appear to be more salient in memory. These results provide evidence that haptic effects have the potential to improve children's reading experience and make it more memorable.

Handheld and wearable devices frequently engage users with simple haptic feedback, such as alerting, shaking, and pulsating. Here we explored intermanual apparent tactile motion-illusory movement between two hands-as a means to enrich such feedback. A series of psychophysical experiments determined the control space for generating smooth and consistent motion across the hands while users held the device. Experiment 1 calibrated the system and showed that vibrotactile detection thresholds decreased with increasing frequency, with similar trends for both hands. Experiment 2 measured effects of vibrotactile parameters on perceived motion. Both duration and temporal separation of stimuli, but not frequency and amplitude, affected subjective motion ratings. In Experiment 3, subjective ratings showed that stimuli with gradual onsets produced a stronger percept of motion than those with abrupt onsets. Finally, Experiment 4 determined a multimodal factor to match moving visual cues across the screen to moving tactile motion across hands. Our results showed compression of visual duration by the tactile system by a factor of approximately 1/3 at two test frequencies. The results of this research are useful for media designers and developers to generate reliable motion across the hands and integrate haptic motion with visual media.

Chairs, wearables, and handhelds have become popular sites for spatial tactile display. Visual animators, already expert in using time and space to portray motion, could readily transfer their skills to produce rich haptic sensations if given the right tools. We introduce the tactile animation object, a directly manipulated phantom tactile sensation. This abstraction has two key benefits: 1) efficient, creative, iterative control of spatiotemporal sensations, and 2) the potential to support a variety of tactile grids, including sparse displays. We present Mango, an editing tool for animators, including its rendering pipeline and perceptually-optimized interpolation algorithm for sparse vibrotactile grids. In our evaluation, professional animators found it easy to create a variety of vibrotactile patterns, with both experts and novices preferring the tactile animation object over controlling actuators individually.

Despite a long history of use in communication, haptic feedback is a relatively new addition to the toolbox of special effects. Unlike artists who use sound or vision, haptic designers cannot simply access libraries of effects that map cleanly to media content, and they lack even guiding principles for creating such effects. In this article, we make progress toward both capabilities: we generate a foundational library of usable haptic vocabulary and do so with a methodology that allows ongoing additions to the library in a principled and effective way. We define a feel effect as an explicit pairing between a meaningful linguistic phrase and a rendered haptic pattern. Our initial experiment demonstrates that users who have only their intrinsic language capacities, and no haptic expertise, can generate a core set of feel effects that lend themselves via semantic inference to the design of additional effects. The resulting collection of more than 40 effects covers a wide range of situations (including precipitation, animal locomotion, striking, and pulsating events) and is empirically shown to produce the named sensation for the majority of our test users in a second experiment. Our experiments demonstrate a unique and systematic approach to designing a vocabulary of haptic sensations that are related in both the semantic and parametric spaces.

We present a tactile-rendering algorithm for simulating 3D geometric features, such as bumps, on touch screen surfaces. This is achieved by modulating friction forces between the user's finger and the touch screen, instead of physically moving the touch surface. We proposed that the percept of a 3D bump is created when local gradients of the rendered virtual surface are mapped to lateral friction forces. To validate this approach, we first establish a psychophysical model that relates the perceived friction force to the controlled voltage applied to the tactile feedback device. We then use this model to demonstrate that participants are three times more likely to prefer gradient force profiles than other commonly used rendering profiles. Finally, we present a generalized algorithm and conclude the paper with a set of applications using our tactile rendering technology.

AIREAL is a novel haptic technology that delivers effective and expressive tactile sensations in free air, without requiring the user to wear a physical device. Combined with interactive computers graphics, AIREAL enables users to feel virtual 3D objects, experience free air textures and receive haptic feedback on gestures performed in free space. AIREAL relies on air vortex generation directed by an actuated flexible nozzle to provide effective tactile feedback with a 75 degrees field of view, and within an 8.5cm resolution at 1 meter. AIREAL is a scalable, inexpensive and practical free air haptic technology that can be used in a broad range of applications, including gaming, mobile applications, and gesture interaction among many others. This paper reports the details of the AIREAL design and control, experimental evaluations of the device's performance, as well as an exploration of the application space of free air haptic displays. Although we used vortices, we believe that the results reported are generalizable and will inform the design of haptic displays based on alternative principles of free air tactile actuation.

This studio proposes to tangibly explore the world of haptics to develop a greater understanding and sensitivity to this emerging field. The first part of the studio focuses on general knowledge about haptics, haptic and multimodal perception in humans, and key advances in actuator and sensor technologies to develop haptic interfaces. Numerous demos and testing platforms will be available to relate discussions with real haptic sensations. The second part of the studio aims to explore the various challenges and difficulties in designing haptic interfaces by directly building and sketching in hardware haptic interfaces. Participants will be invited to build their own haptic interfaces from various actuators, sensors and other building blocks. The studio aims to bridge the fields of haptics and design, and investigate various prototyping tools and approaches that can best support haptic design activities.

Tactile Brush is an algorithm that produces smooth, two-dimensional tactile moving strokes with varying frequency, intensity, velocity and direction of motion. The design of the algorithm is derived from the results of psychophysical investigations of two tactile illusions -- apparent tactile mo-tion and phantom sensations. Combined together they allow for the design of high-density two-dimensional tactile displays using sparse vibrotactile arrays. In a series of experiments and evaluations we demonstrate that Tactile Brush is robust and can reliably generate a wide variety of moving tactile sensations for a broad range of applications.

We explore the effects of parameters constituting a second order dynamic system on the rate of human motor adaptation while performing a rhythmic dynamic task. In our experiments, participants excite virtual second-order systems at resonance via a haptic interface. After overtraining subjects with a nominal system, we unexpectedly change the system parameters and study the resulting motor adaptation in catch trials. Through four experiment seatings, we demonstrate the effects of dynamic system parameters on human motor adaptation. Results indicate that gain and damping parameters significantly affect the rate of adaptation. In particular, as the effort required to complete the task increases, the rate of adaptation decreases, indicating a trade-off between task performance and the effort required to perform the task.

In this paper we present three experiments to measure the control parameter space of apparent haptic motion using a variety of stimulation attributes and body sites. In Experiment 1 we measured the range of Stimulus Onset Asynchrony (SOA) that created the percept of continuous motion between two vibrating points on the dorsal forearm and on the back by varying the frequency, intensity and duration of stimulation. The SOA space for apparent motion varied with duration and body site but not with frequency and intensity of stimulation. In Experiment 2 we measured the SOA space for moving sensations when direction of motion and spacing between actuators were varied. On the forearm the SOA space was influenced by both the direction and spacing. However, on the back it was only affected by the direction of actuation. Finally, in Experiment 3 we measured the SOA space using four or more actuation points, creating two-dimensional apparent motion. The results of the present study are discussed in the context of designing haptic contents for movies, amusement rides and video games.

We present a new technology for enhancing touch interfaces with tactile feedback. The proposed technology is based on the electrovibration principle, does not use any moving parts and provides a wide range of tactile feedback sensations to fingers moving across a touch surface. When combined with an interactive display and touch input, it enables the design of a wide variety of interfaces that allow the user to feel virtual elements through touch. We present the principles of operation and an implementation of the technology. We also report the results of three controlled psychophysical experiments and a subjective user evaluation that describe and characterize users' perception of this technology. We conclude with an exploration of the design space of tactile touch screens using two comparable setups, one based on electrovibration and another on mechanical vibrotactile actuation.

We report position and force detection thresholds for sinusoidal waveforms in the frequency range 10-500 Hz delivered through a stylus. The participants were required to hold the stylus in a way similar to that of holding the stylus of a force-feedback device. A minishaker moved the stylus along its length so that the majority of vibrations were presented tangentially to the skin of the hand. The measured position thresholds decreased initially with an increasing stimulus frequency and formed a U-shaped curve in the high frequency region. The thresholds of high frequency vibrations were lower than those reported previously for vibrations that were perpendicular to the skin, but were similar to the thresholds reported earlier using vibrations that were tangential to the skin. A similar force threshold curve was obtained using a force sensor attached to one end of the stylus. Mechanical impedance of the skin derived from velocity estimates and force measurements indicated that the skin and tissues in the hand holding the stylus can be modeled with mass-, damper- and spring-like elements. A comparison of the mechanical impedance from the present study with those reported previously showed similar results for vibrations delivered in the tangential and normal directions to the skin