An Evaluation Testbed for Locomotion in Virtual Reality Cannavo, Alberto; Calandra, Davide; Prattico, F. Gabriele ...
IEEE transactions on visualization and computer graphics,
2021-March-1, 2021-Mar, 2021-3-1, 20210301, Volume:
27, Issue:
3
Journal Article
Peer reviewed
Open access
A common operation performed in Virtual Reality (VR) environments is locomotion. Although real walking can represent a natural and intuitive way to manage displacements in such environments, its use ...is generally limited by the size of the area tracked by the VR system (typically, the size of a room) or requires expensive technologies to cover particularly extended settings. A number of approaches have been proposed to enable effective explorations in VR, each characterized by different hardware requirements and costs, and capable to provide different levels of usability and performance. However, the lack of a well-defined methodology for assessing and comparing available approaches makes it difficult to identify, among the various alternatives, the best solutions for selected application domains. To deal with this issue, this article introduces a novel evaluation testbed which, by building on the outcomes of many separate works reported in the literature, aims to support a comprehensive analysis of the considered design space. An experimental protocol for collecting objective and subjective measures is proposed, together with a scoring system able to rank locomotion approaches based on a weighted set of requirements. Testbed usage is illustrated in a use case requesting to select the technique to adopt in a given application scenario.
Modern electronic devices and novel materials often derive their extraordinary properties from the intriguing, complex behavior of large numbers of electrons forming what is known as an electron ...liquid. This book provides an in-depth introduction to the physics of the interacting electron liquid in a broad variety of systems, including metals, semiconductors, artificial nano-structures, atoms and molecules. One, two and three dimensional systems are treated separately and in parallel. Different phases of the electron liquid, from the Landau Fermi liquid to the Wigner crystal, from the Luttinger liquid to the quantum Hall liquid are extensively discussed. Both static and time-dependent density functional theory are presented in detail. Although the emphasis is on the development of the basic physical ideas and on a critical discussion of the most useful approximations, the formal derivation of the results is highly detailed and based on the simplest, most direct methods.
The investigation of factors contributing at making humans trust Autonomous Vehicles (AVs) will play a fundamental role in the adoption of such technology. The user's ability to form a mental model ...of the AV, which is crucial to establish trust, depends on effective user-vehicle communication; thus, the importance of Human-Machine Interaction (HMI) is poised to increase. In this work, we propose a methodology to validate the user experience in AVs based on continuous, objective information gathered from physiological signals, while the user is immersed in a Virtual Reality-based driving simulation. We applied this methodology to the design of a head-up display interface delivering visual cues about the vehicle's sensory and planning systems. Through this approach, we obtained qualitative and quantitative evidence that a complete picture of the vehicle's surrounding, despite the higher cognitive load, is conducive to a less stressful experience. Moreover, after having been exposed to a more informative interface, users involved in the study were also more willing to test a real AV. The proposed methodology could be extended by adjusting the simulation environment, the HMI and/or the vehicle's Artificial Intelligence modules to dig into other aspects of the user experience.
Providing pedestrians and other vulnerable road users with a clear indication about a fully autonomous vehicle status and intentions is crucial to make them coexist. In the last few years, a variety ...of external interfaces have been proposed, leveraging different paradigms and technologies including vehicle-mounted devices (like LED panels), short-range on-road projections, and road infrastructure interfaces (e.g., special asphalts with embedded displays). These designs were experimented in different settings, using mockups, specially prepared vehicles, or virtual environments, with heterogeneous evaluation metrics. Promising interfaces based on Augmented Reality (AR) have been proposed too, but their usability and effectiveness have not been tested yet. This paper aims to complement such body of literature by presenting a comparison of state-of-the-art interfaces and new designs under common conditions. To this aim, an immersive Virtual Reality-based simulation was developed, recreating a well-known scenario represented by pedestrians crossing in urban environments under non-regulated conditions. A user study was then performed to investigate the various dimensions of vehicle-to-pedestrian interaction leveraging objective and subjective metrics. Even though no interface clearly stood out over all the considered dimensions, one of the AR designs achieved state-of-the-art results in terms of safety and trust, at the cost of higher cognitive effort and lower intuitiveness compared to LED panels showing anthropomorphic features. Together with rankings on the various dimensions, indications about advantages and drawbacks of the various alternatives that emerged from this study could provide important information for next developments in the field.
Background
In the evaluation of the facial aging, the midface certainly represents the part that undergoes the most modifications and in which the aging process is most evident. The filling and ...redefinition of this part are fundamental to modify the perception of the age of the face and create a global rejuvenation effect. In general, high G’ fillers with a deep implant are used to treat the midface, taking advantage of the high lifting capacity and persistence of the implant in place.
Methods
We report our experience in the treatment of 20 patients with a hyaluronic acid (HA) filler based on an innovative crosslinking technology (XTR™—eXcellent Tridimensional Reticulation) for midface treatment. GAIS (Global Aesthetic Improvement Scale) at 1 month and 3 months after treatment was evaluated as primary endpoint. Patient satisfaction with the overall appearance, repeatability of treatment, and also an instrumental evaluation of the improvement were performed.
Results
Global Aesthetic Improvement Scale and patient satisfaction were very good 1 month and 3 months after treatment. The majority of patients said they would undergo treatment again. Clinical results were confirmed by instrumental evaluation.
Conclusion
The treatment of midface with this innovative HA high G’ filler is really effective in restoration of the volumes and in reshaping the curves of zygomatic area.
Background: Calcium hydroxylapatite (CaHA, Radiesse®) with integral 0.3% lidocaine (CaHA(+)) has recently been approved for use in aesthetic medicine. This study assessed the performance of CaHA(+) ...in subjects undergoing treatment for facial volume loss and evaluated subject and physician satisfaction.
Methods: In a prospective, open-label, post-marketing study, 25 women seeking treatment for age-related facial volume loss received CaHA(+) injections in 1–3 facial areas including the cheeks, marionette lines, prejowl sulcus, and jawline. Subjects returned for follow-up at 14 and 120 days, with the option of touch-up injections at day 14 if required to achieve optimal correction. Filler performance was assessed using the Merz Aesthetics Scales (MAS) and subject satisfaction using the Global Impression of Change Scale (GICS). Physician satisfaction was assessed in terms of CaHA(+)-related properties (eg, ease of injection, distribution, positioning) and aesthetic outcomes. Adverse events were recorded.
Results: Mean MAS scores at baseline were ~2 corresponding to moderate facial volume loss/sagging in the treated area. At day 14, the mean score had improved to ≤1.4 for all treated areas, indicating mild volume loss. At day 120, mean scores had further improved to ≤1.1. At both follow-up visits, mean GICS scores were ≥2 indicating facial appearance was ‘much improved’ compared with baseline. All subjects reported willingness to repeat treatment and recommend it to family/friends. Physician ratings were high for ease of CaHA(+) injection, distribution, positioning, sculpturing outcome, and effect on skin tension. Compared to CaHA without lidocaine, the physician rated CaHA(+) as better or similar in performance. Adverse events were mostly mild and expected with CaHA and filler injections in general.
Conclusion: The well-established efficacy and safety profile of CaHA appears unchanged by the addition of integral lidocaine. CaHA(+) was effective for volume enhancement in a number of facial areas and associated with high subject and physician satisfaction.
J Drugs Dermatol. 2019;18(1):86-91.
The latest advances in a GaN on SiC RF technology for powering radar systems and particle accelerators are reported. Unlike research-grade technologies based on novel materials, the technology ...presented here is highly manufacturable as it is based on commercially available GaN on SiC epitaxial wafers and the AlGaN/GaN high electron mobility transistor (HEMT) structure. However, compared to state-of-the-art GaN on SiC RF technology operating from 28 to 50 V, the approach and results presented in this paper explore core transistor designs that are suitable for operation with a bias voltage ranging from 75 to 150 VDC. Wafer processing is similar to typical GaN HEMT process modules for commercially available 28 - 50 V technology and therefore can be easily implemented in existing GaN on SiC manufacturing lines. The approach results in power densities > 10 W/mm at hundred watts power levels which is very desirable in mega-watts RF systems. The results presented in this publication illustrate some of the benefits achievable in radar systems and RF power sources for particle accelerators.
In the context of Industry 4.0, a paradigm shift from traditional industrial manipulators to Collaborative Robots (CRs) is ongoing, with the latter serving ever more closely humans as auxiliary tools ...in many production processes. In this scenario, continuous technological advancements offer new opportunities for further innovating robotics and other areas of next-generation industry. For example, 6G could play a prominent role due to its human-centric view of the industrial domains. In particular, its expected dependability features will pave the way for new applications exploiting highly effective Digital Twin (DT)- and eXtended Reality (XR)-based telepresence. In this work, a novel application for the above technologies allowing two distant users to collaborate in the programming of a CR is proposed. The approach encompasses demanding data flows (e.g., point cloud-based streaming of collaborating users and robotic environment), with network latency and bandwidth constraints. Results obtained by analyzing this approach from the viewpoint of network requirements in a setup designed to emulate 6G connectivity indicate that the expected performance of forthcoming mobile networks will make it fully feasible in principle.
Abstract
Cinematic virtual reality (CVR) offers filmmakers a wide range of possibilities to explore new techniques regarding movie scripting, shooting and editing. Despite the many experiments ...performed so far both with both live action and computer-generated movies, just a few studies focused on analyzing how the various techniques actually affect the viewers’ experience. Like in traditional cinema, a key step for CVR screenwriters and directors is to choose from which perspective the viewers will see the scene, the so-called point of view (POV). The aim of this paper is to understand to what extent watching an immersive movie from a specific POV could impact the narrative engagement (NE), i.e., the viewers’ sensation of being immersed in the movie environment and being connected with its characters and story. Two POVs that are typically used in CVR, i.e., first-person perspective (1-PP) and external perspective (EP), are investigated through a user study in which both objective and subjective metrics were collected. The user study was carried out by leveraging two live action 360° short films with distinct scripts. The results suggest that the 1-PP experience could be more pleasant than the EP one in terms of overall NE and narrative presence, or even for all the NE dimensions if the potential of that POV is specifically exploited.
Evidence is presented for the finite wave vector crossing of the two lowest one-dimensional spin-split subbands in quantum point contacts fabricated from two-dimensional hole gases with strong ...spin-orbit interaction. This phenomenon offers an elegant explanation for the anomalous sign of the spin polarization filtered by a point contact, as observed in magnetic focusing experiments. Anticrossing is introduced by a magnetic field parallel to the channel or an asymmetric potential transverse to it. Controlling the magnitude of the spin splitting affords a novel mechanism for inverting the sign of the spin polarization.
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