Presenting Morphing Shape Illusion: Enhanced Sense of Morphing Virtual Object With Weight Shifting VR Controller by Computational Perception Model.

The haptic sensation is crucial for virtual reality, as it gives the presence of objects in a virtual world and thus gives a greater sense of immersion. To provide a sense of the shape of handheld objects, a haptic device that changes weight distribution is proposed. It is known that the visual feedback enhances the haptic sensation of shape, and it is also known that it does for morphing shape as well. Our previous publication presented a perception model for the static shape of a virtual object. In this article, we extend the model to produce a plausible sense of the morphing shape of handheld objects. Our stochastic model predicts the proper weight actuation for the weight-shifting haptic device, which users can plausibly feel while reducing hardware effort. We evaluated our perception model and resulted in the model accuracy average of 8.1% error. Using this perception model, the amount of weight actuation at 75% probability of plausibility is reduced up to 37%.

Effects of Collaborative Training Using Virtual Co-embodiment on Motor Skill Learning.

Virtual reality (VR) is a promising tool for motor skill learning. Previous studies have indicated that observing and following a teacher's movements from a first-person perspective using VR facilitates motor skill learning. Conversely, it has also been pointed out that this learning method makes the learner so strongly aware of the need to follow that it weakens their sense of agency (SoA) for motor skills and prevents them from updating the body schema, thereby preventing long-term retention of motor skills. To address this problem, we propose applying "virtual co-embodiment" to motor skill learning. Virtual co-embodiment is a system in which a virtual avatar is controlled based on the weighted average of the movements of multiple entities. Because users in virtual co-embodiment overestimate their SoA, we hypothesized that learning using virtual co-embodiment with a teacher would improve motor skill retention. In this study, we focused on learning a dual task to evaluate the automation of movement, which is considered an essential element of motor skills. As a result, learning in virtual co-embodiment with the teacher improves motor skill learning efficiency compared with sharing the teacher's first-person perspective or learning alone.

Virtual Co-Embodiment: Evaluation of the Sense of Agency While Sharing the Control of a Virtual Body Among Two Individuals.

In this article, we introduce a concept called "virtual co-embodiment", which enables a user to share their virtual avatar with another entity (e.g., another user, robot, or autonomous agent). We describe a proof-of-concept in which two users can be immersed from a first-person perspective in a virtual environment and can have complementary levels of control (total, partial, or none) over a shared avatar. In addition, we conducted an experiment to investigate the influence of users' level of control over the shared avatar and prior knowledge of their actions on the users' sense of agency and motor actions. The results showed that participants are good at estimating their real level of control but significantly overestimate their sense of agency when they can anticipate the motion of the avatar. Moreover, participants performed similar body motions regardless of their real control over the avatar. The results also revealed that the internal dimension of the locus of control, which is a personality trait, is negatively correlated with the user's perceived level of control. The combined results unfold a new range of applications in the fields of virtual-reality-based training and collaborative teleoperation, where users would be able to share their virtual body.

Effect of Avatar Appearance on Detection Thresholds for Remapped Hand Movements.

Hand interaction techniques in virtual reality often exploit visual dominance over proprioception to remap physical hand movements onto different virtual movements. However, when the offset between virtual and physical hands increases, the remapped virtual hand movements are hardly self-attributed, and the users become aware of the remapping. Interestingly, the sense of self-attribution of a body is called the sense of body ownership (SoBO) in the field of psychology, and the realistic the avatar, the stronger is the SoBO. Hence, we hypothesized that realistic avatars (i.e., human hands) can foster self-attribution of the remapped movements better than abstract avatars (i.e., spherical pointers), thus making the remapping less noticeable. In this article, we present an experiment in which participants repeatedly executed reaching movements with their right hand while different amounts of horizontal shifts were applied. We measured the remapping detection thresholds for each combination of shift directions (left or right) and avatar appearances (realistic or abstract). The results show that realistic avatars increased the detection threshold (i.e., lowered sensitivity) by 31.3 percent than the abstract avatars when the leftward shift was applied (i.e., when the hand moved in the direction away from the body-midline). In addition, the proprioceptive drift (i.e., the displacement of self-localization toward an avatar) was larger with realistic avatars for leftward shifts, indicating that visual information was given greater preference during visuo-proprioceptive integration in realistic avatars. Our findings quantifiably show that realistic avatars can make remapping less noticeable for larger mismatches between virtual and physical movements and can potentially improve a wide variety of hand-remapping techniques without changing the mapping itself.

Improvement of driver active interventions during automated driving by displaying trajectory pointers-A driving simulator study.

Objective: The handover of vehicle control from automated to manual operation is a critical aspect of interaction between drivers and automated driving systems (ADS). In some cases, it is possible that the ADS may fail to detect an object. In this event, the driver must be aware of the situation and resume control of the vehicle without assistance from the system. Consequently, the driver must fulfill the following 2 main roles while driving: (1) monitor the vehicle trajectory and surrounding traffic environment and (2) actively take over vehicle control if the driver identifies a potential issue along the trajectory. An effective human-machine interface (HMI) is required that enables the driver to fulfill these roles. This article proposes an HMI that constantly indicates the future position of the vehicle. Methods: This research used the Toyota Dynamic Driving Simulator to evaluate the effect of the proposed HMI and compares the proposed HMI with an HMI that notifies the driver when the vehicle trajectory changes. A total of 48 test subjects were divided into 2 groups of 24: One group used the HMI that constantly indicated the future position of the vehicle and the other group used the HMI that provided information when the vehicle trajectory changed. The following instructions were given to the test subjects: (1) to not hold the steering wheel and to allow the vehicle to drive itself, (2) to constantly monitor the surrounding traffic environment because the functions of the ADS are limited, and (3) to take over driving if necessary. The driving simulator experiments were composed of an initial 10-min acclimatization period and a 10-min evaluation period. Approximately 10 min after the start of the evaluation period, a scenario occurred in which the ADS failed to detect an object on the vehicle trajectory, potentially resulting in a collision if the driver did not actively take over control and manually avoid the object. Results: The collision avoidance rate of the HMI that constantly indicated the future position of the vehicle was higher than that of the HMI that notified the driver of trajectory changes, χ2 = 6.38, P < .05. The steering wheel hands-on and steering override timings were also faster with the proposed HMI (t test; P < .05). Conclusions: This research confirmed that constantly indicating the position of the vehicle several seconds in the future facilitates active driver intervention when an ADS is in operation.

Ascending and Descending in Virtual Reality: Simple and Safe System Using Passive Haptics.

This paper presents a novel interactive system that provides users with virtual reality (VR) experiences, wherein users feel as if they are ascending/descending stairs through passive haptic feedback. The passive haptic stimuli are provided by small bumps under the feet of users; these stimuli are provided to represent the edges of the stairs in the virtual environment. The visual stimuli of the stairs and shoes, provided by head-mounted displays, evoke a visuo-haptic interaction that modifies a user's perception of the floor shape. Our system enables users to experience all types of stairs, such as half-turn and spiral stairs, in a VR setting. We conducted a preliminary user study and two experiments to evaluate the proposed technique. The preliminary user study investigated the effectiveness of the basic idea associated with the proposed technique for the case of a user ascending stairs. The results demonstrated that the passive haptic feedback produced by the small bumps enhanced the user's feeling of presence and sense of ascending. We subsequently performed an experiment to investigate an improved viewpoint manipulation method and the interaction of the manipulation and haptics for both the ascending and descending cases. The experimental results demonstrated that the participants had a feeling of presence and felt a steep stair gradient under the condition of haptic feedback and viewpoint manipulation based on the characteristics of actual stair walking data. However, these results also indicated that the proposed system may not be as effective in providing a sense of descending stairs without an optimization of the haptic stimuli. We then redesigned the shape of the small bumps, and evaluated the design in a second experiment. The results indicated that the best shape to present haptic stimuli is a right triangle cross section in both the ascending and descending cases. Although it is necessary to install small protrusions in the determined direction, by using this optimized shape the users feeling of presence of the stairs and the sensation of walking up and down was enhanced.

Simplification of olfactory stimuli in pseudo-gustatory displays.

In this paper, we propose a technique that simplifies pseudo-gustatory systems by using the cross-modal effect between vision and olfaction to change only the visual and olfactory stimuli without altering the ingredients of the food. Conventional pseudo-gustatory simulations require one olfactory stimulus for each flavor. In contrast, we hypothesize that the cross-modal effect between vision and olfaction in a pseudo-gustatory presentation can be utilized to reduce the required number of olfactory stimuli, and verify this hypothesis using a pseudo-gustatory display with our proposed method. This pseudo-gustatory display uses the visual-olfactory cross-modal effect and the key scent components decided on the basis of similarity analysis of olfactory perception. We also investigate how users perceive the taste of a drink under various visual and olfactory conditions, both with and without the visual-olfactory interactions. Our results indicate that the cross-modal effect between vision and olfaction can effectively simplify pseudo-gustatory simulations.

3D user interfaces: new directions and perspectives.

Three-dimensional user interfaces (3D UIs) let users interact with virtual objects, environments, or information using direct 3D input in the physical and/or virtual space. In this article, the founders and organizers of the IEEE Symposium on 3D User Interfaces reflect on the state of the art in several key aspects of 3D UIs and speculate on future research.

Extracting alpha band modulation during visual spatial attention without flickering stimuli using common spatial pattern.

In this paper, alpha band modulation during visual spatial attention without visual stimuli was focused. Visual spatial attention has been expected to provide a new channel of non-invasive independent brain computer interface (BCI), but little work has been done on the new interfacing method. The flickering stimuli used in previous work cause a decline of independency and have difficulties in a practical use. Therefore we investigated whether visual spatial attention could be detected without such stimuli. Further, the common spatial patterns (CSP) were for the first time applied to the brain states during visual spatial attention. The performance evaluation was based on three brain states of left, right and center direction attention. The 30-channel scalp electroencephalographic (EEG) signals over occipital cortex were recorded for five subjects. Without CSP, the analyses made 66.44 (range 55.42 to 72.27) % of average classification performance in discriminating left and right attention classes. With CSP, the averaged classification accuracy was 75.39 (range 63.75 to 86.13) %. It is suggested that CSP is useful in the context of visual spatial attention, and the alpha band modulation during visual spatial attention without flickering stimuli has the possibility of a new channel for independent BCI as well as motor imagery.

Non-target photo images in oddball paradigm improve EEG-based personal identification rates.

A research on biometry based on human brain activities has lately been emerging. In this study, we investigate the feasibility of personal identification using one-channel electroencephalogram during photo retrieval in oddball paradigm. The use of non-target photo images was examined to improve the identification performances. Nine photo images were randomly presented one after another to five subjects. The Principal Component Analysis and the Linear Discriminant Analysis were applied for the signal processing. With EEG activities both during target and non-target photo retrieval, the algorithm successfully improved the identification rates. The rates were 87.2, 95.0, and 97.6% using 5, 10, and 20-time averaging, respectively. The performances with EEG only during target photo retrieval were lower by 5-13%. This study reveals a future possibility of photo retrieval tasks to realize the personal identification using human brain activities, which will yield rich controls of machine for the users of brain computer-interface.

Noise reduction from genotyping microarrays using probe level information.

Genomic copy number change is one of the important phenomenon observed in cancer and other genetic disorders. Recently oligonucleotide microarrays have been used to analyze changes in the copy number. Although high density microarrays provide genome wide useful data on copy number, they are often associated with substantial amount of experimental noise that could affect the performance of the analyses. We used the high density oligonucleotide genotyping microarrays in our experiments that uses redundant probe tiling approach for individual SNPs. We found that the noise in the genotyping microarray data is associated with several experimental steps during target preparation and devised an algorithm that takes into account those experimental parameters. Additionally, defective probes that do not hybridize well to the target and therefore could not be modified inherently were detected and omitted automatically by using the algorithm. When we applied the algorithm to actual datasets, we could reduce the noise substantially without compressing the dynamic range. Additionally, combinatorial use of our noise reduction algorithm and conventional breakpoint detection algorithm successfully detected a microamplification of c-myc which was overlooked in the raw data. The algorithm described here is freely available with the software upon request to all non-profit researchers.

A novel immunomodulator, FTY720, prevents development of experimental autoimmune myasthenia gravis in C57BL/6 mice.

Prophylactic oral administration of a novel immunomodulator (immunosuppressant), FTY720 (1 mg/kg, three times a week), completely prevented the development of experimental autoimmune myasthenia gravis (EAMG) in C57BL/6 mice. EAMG has been used as an animal model for human myasthenia gravis, and was established by immunizing the mice with acetylcholine receptor (AChR) from Torpedo californica. FTY720 also suppressed the production of both anti-Torpedo californica AChR antibody and anti-mouse AChR autoantibody by the mice, which were observed in mice in which EAMG had become established. These results strongly suggest that FTY720 is a promising candidate for treatment of human myasthenia gravis.

Expression imbalance map: a new visualization method for detection of mRNA expression imbalance regions.

We describe the development of a new visualization method, called the expression imbalance map (EIM), for detecting mRNA expression imbalance regions, reflecting genomic losses and gains at a much higher resolution than conventional technologies such as comparative genomic hybridization (CGH). Simple spatial mapping of the microarray expression profiles on chromosomal location provides little information about genomic structure, because mRNA expression levels do not completely reflect genomic copy number and some microarray probes would be of low quality. The EIM, which does not employ arbitrary selection of thresholds in conjunction with hypergeometric distribution-based algorithm, has a high tolerance of these complex factors. The EIM could detect regionally underexpressed or overexpressed genes (called, here, an expression imbalance region) in lung cancer specimens from their gene expression data of oligonucleotide microarray. Many known as well as potential loci with frequent genomic losses or gains were detected as expression imbalance regions by the EIM. Therefore, the EIM should provide the user with further insight into genomic structure through mRNA expression.