A significant problem in brain-computer interface (BCI) research is decoding - obtaining required information from very weak noisy electroencephalograph signals and extracting considerable information from limited data. Traditional intention decoding methods, which obtain information from induced or spontaneous brain activity, have shortcomings in terms of performance, computational expense and usage burden. Here, a new methodology called prediction error decoding was used for motor imagery (MI) detection and compared with direct intention decoding. Galvanic vestibular stimulation (GVS) was used to induce subliminal sensory feedback between the forehead and mastoids without any burden. Prediction errors were generated between the GVS-induced sensory feedback and the MI direction. The corresponding prediction error decoding of the front/back MI task was validated. A test decoding accuracy of 77.83-78.86% (median) was achieved during GVS for every 100[Formula: see text]ms interval. A nonzero weight parameter-based channel screening (WPS) method was proposed to select channels individually and commonly during GVS. When the WPS common-selected mode was compared with the WPS individual-selected mode and a classical channel selection method based on correlation coefficients (CCS), a satisfactory decoding performance of the selected channels was observed. The results indicated the positive impact of measuring common specific channels of the BCI.

Galvanic vestibular stimulation induces virtual acceleration sensation and is expected to be applied in computer games to improve their reality. The acceleration sensation can be enhanced by giving countercurrent which consists of an opposite current part and a forwarding current part. Conventionally, however, the degree of the enhancement is uncontrollable. This study reports that the effect of countercurrent can be modeled by an electrical circuit containing a capacitor and resistors. To model the effect of the countercurrent on the acceleration perception, we investigated the relation between the parameters: the duration and the strength of the opposite current part, of the countercurrent and strength of acceleration perception. The results of our study show that the strength of the acceleration sensation induced by the countercurrent stimulation has a nonlinear correlation with the duration of the opposite current, and the characteristics of the enhancement effect can be estimated using a CR circuit model.

The mechanism by which cathodal current stimulation exerts inhibitory effects on the five basic tastes is revealed herein. The objective of this paper is to successfully achieve inhibition of sweetness by cathodal current electrical stimulation to the tongue, which has not been reported to date, though inhibition of salty and umami perception has been documented. By focusing on the electrophoresis of ions generated by dissolution of taste-inducing substances in water, this paper indicates how human gustation is inhibited by electrical stimulation, which is a key addition to the knowledgebase for achieving control of all five basic tastes.

As a low-cost information display in public spaces, we achieved a multi-slit display by the arrangement of LED columns. Multi-slits visually present an image pattern through columns of slits that are arranged several spaces wide. They cannot be perceived image by stop patterns, but they can be perceived by scroll patterns. In this paper, we experimentally show that stereoscopic vision is possible by presenting binocular parallax images that impart the beam direction from slits.

Our aim of this study is to investigate the possibility of estimating interruptibility from Electroencephalograms (EEG). We focus on contingent negative variation which is elicited in response to concentration. Our results support that our method could correctly detects the user's internal states such as just watching or actively remembering even the external situations were completely same and also CNV is elicited when controlling continuous motion.

Empathy is important for our society and individuals, since it is what facilitates our interactions and connections to the other people around us. Our experience-based installation "empathetic heartbeat" aims to have the participant remind the existence of his/her heart in the internal body and recognize that our bodies are medium for feeling empathy with others. Here we describe the concept of the installation and participant's experience.

In this paper, we propose novel software to read text documents with tablet PCs and describe its installation plan. The software, "Yu bi Yomu," was developed as an iOS application, supposing to work on the Apple iPad. In that software, the contrast of displayed texts is changed dynamically in response to users' trailing behavior. In the installation, we will project the displays of tablet PCs operating "Yu bi Yomu" onto large screens attached to the wall or floor. The installation using this novel software provides new reading experiences.

When training for dance or sports, amateurs observe and mimic the physical exertion of experts to acquire skill by observing others. However, humans don't memorize consecutive operations, but instead make discrete divisions and memorize body movements. The posture that becomes a key from consecutive operations is removed and memorized for discretion in a process we call segmentation. The movement is reproduced by smooth interpolations between the clause and the clause memorized as segmentation. In the first experiment, we clarified the existence of this segmentation by showing video of smooth movements to participants who selected the segment/frame that became a key. We confirmed commonness in this segment selection. In experiment 2, to reflect the physical exertion that made the segmentation, the participants input force to force sensors by a control stick. We showed video of smooth movements to them and simultaneously input the force pattern that corresponds to the movement. The force pattern, which uniformly converges by such repetition, is different depending on each participant. We call this method the “extraction of segmented behavioral intention.” On the other hand, we can arbitrarily change the speed of the physical exertion by expanding and contracting the segments of the movement video that obtained the force pattern by “extraction of segmented behavioral intention.” Since the expanded and contracted pattern range at a certain speed even when the movement speed changed, we preserved the shape and the selected segments. However, the segment shape changes when the movement speed is constantly fast.

This study presents an experiment that integrates a semiotic investigation with a dynamical perspective on embodied social interactions. The primary objective is to study co-creativity of a communication system on the human-human nonverbal interaction. Throughout the experiment, the results of established communication system on uni- and bi-directional interactions are compared. Finally, the role of co-creativity in the evolution of communication systems will be discussed.

We developed a new pseudo-attraction force display using four vibrating motors. The advantage of this device is that it uses phase difference control to alter the time width of pulses to generate asymmetric oscillation. It does not require altering the frequency of the vibrating motors. In this study, we investigated the influence of the pulse width generated in the device using vibrating motors on the perceptive intensity of pseudo-attraction force. From the result, the oscillation having shorter pulse widths within the range of 10-20 ms induced the “being-pulled” sensation more strongly.

Our aim of this paper is to investigate the human communication in terms of two following questions. One is how human can know the fact that an interacting partner is human. Another is how non-communicative behaviour can become communicative. To answer these questions, we performed two experiments exploiting the idea of perceptual crossing experiments. As a result, we will show that the turn-taking structure supports humanlikeness and human communication in the primitive non-verbal interaction. Our results will be discussed with ambient interface technology.

When a single column of light sources flashes quickly in a temporal pattern during a horizontal saccade eye movement, two-dimensional images can be perceived in the space neighboring the light source. This perceptual phenomenon has been applied to light devices for visual arts and entertainment. However, a serious drawback in exploiting this perceptual phenomenon for a visual information display is that a two-dimensional image cannot be viewed if there is any discrepancy between the ocular motility and the flicker timing. We overcame this drawback by combining the saccade-based display with an electro-ocular-graph-based sensor for detecting the saccade. The saccade onset is measured with the electro-ocular-graph-based sensor in real time and the saccade-based display is activated instantaneously as the saccade begins. The psychophysical experiments described in this article demonstrates that the method that we used can detect saccades with low latency and allows the saccade-based display to convey visual information more effectively than when the light sources continuously blink regardless of the observer's eye movements.

Performing general human behavior by experts' navigation is expected to be realized as wearable and ubiquitous technologies and computing develop. For simple, ordinary behavior, a person does not need the assistance of an expert. However, if one is standing next to an injured/ill person, one needs the instruction on performing first aid treatment from an expert. The wearer of the wearable behavior navigation system will be able to conduct first aid treatment as an expert would. We have developed the wearable behavior navigation systems using Augmented Reality technology, mainly for the navigation of the first aid treatment and for escape from dangerous areas, such as a building on fire. The effectiveness of the wearable navigation systems has been evaluated by a number of experiments. In this paper, the basic mechanism to realize general human behavior navigation is presented, along with the concrete configuration of the prototype of the navigation systems, and the experimental evaluation.

This paper discusses the design of a knocking force display to induce the kinesthetic illusion of being pulled. Previously, we have found that when a hand-held object oscillates in the hand, if the acceleration pattern is lopsided, one feels a pulling force sensation, although the object does move in two opposite directions. Here, we designed and developed a new force display to generate two imbalanced acceleration patterns in opposing directions. In the display, an internal mass repetitively collides against a wall, to create a spikier pulse than the previous force display could produce. We determined the circumstances under which the sensation of being pulled was perceived by varying the pulse width, i.e., by attaching materials of different stiffnesses to the wall.

When two distant persons establish cooperative interaction, how to share their motions and sensations and how to adjust or revise their motions are important for cooperation. In this paper, we propose an approach for sharing first-person perspectives to establish collaboration and to transmit a skill from one to another. We developed a view-sharing system to realize such interaction. To investigate the fundamental behavioral property of humans with our system, we examined a simple collaborated behavior and found that a situation where subjects only see their partner's view improves velocity following. By exploiting this property, we transmitted the basic skill required for the Diabolo trick to non-skilled persons. Through our system, the performances of non-skilled persons with the assistance of a skilled person surpassed individual performances.

The capability to perform specific human tasks with the assistance of expert navigation is expected to be realized through the development wearable and ubiquitous computing technology. For instance, when an injured or ill person requires first-aid treatment, but only non-experts are nearby, instruction from an expert at a remote site is necessary. A behavior navigation system will allow the user to provide first-aid treatment in the same manner as an expert. Focusing on first-aid treatment, we have proposed and developed a prototype wearable behavior navigation system (WBNS) that uses augmented reality (AR) technology. This prototype WBNS has been evaluated in experiments, in which participants wore the prototype and successfully administered various first-aid treatments. Although the effectiveness of the WBNS has been confirmed, many challenges must be addressed to commercialize the system. The head-mounted displays (HMDs) used in the WBNS have a number of drawbacks, for example, high cost (which is not expected to decrease in the near future) and the time required for an ordinary user to become accustomed to the display. Furthermore, some individuals may experience motion sickness wearing the HMD. We expect that these drawbacks to the current technology will be resolved in the future; meanwhile, a near-future remote behavior navigation system (RBNS) is necessary. Accordingly, we have developed RBNSs for first-aid treatment using off-the-shelf components, in addition to the WBNS. In this paper, the basic mechanisms of the RBNS, experiments investigating the demonstration of expert behavior, and a comparative study of the WBNS and the RBNSs are presented.

When a small mass in a hand-held device oscillates along a single axis with asymmetric acceleration (strongly peaked in one direction and diffuse in the other), the holder typically experiences a kinesthetic illusion characterized by the sensation of being continuously pushed or pulled by the device. This effect was investigated because of its potential application to a hand-held, nongrounded, haptic device that can convey a sense of a continuous translational force in one direction, which is a key missing piece in haptic research. A 1 degree-of-freedom (DOF) haptic device based on a crank-slider mechanism was constructed. The device converts the constant rotation of an electric motor into the constrained movement of a small mass with asymmetric acceleration. The frequency that maximizes the perceived movement offered by the haptic device was investigated. Tests using three subjects showed that for the prototype, the best frequencies were 5 and 10 cycles per second.

When a small object in a hand-held device moves periodically and prismatically with asymmetric acceleration (strong in one direction and weak in the other), the holder typically experiences the kinesthetic illusion of being pushed or pulled continuously by the held device. We investigated this perceptual effect for its potential application to a hand-held, non-grounded, haptic device that can convey a sense of a continuous translational force in one direction, which is a yet missing tile in haptics research. A one-degree of freedom haptic device based on two symmetric slider-crank mechanism was constructed to convert the single-speed rotational cyclic movement of a motor into asymmetric translational cyclic movement with asymmetric acceleration and to cancel unwanted side acceleration. We verified our previous results with the haptic device and investigated the effect of the gross weight of the device on force perception.

This study describes the relation between the vection produced by optical flow and that created by galvanic vestibular stimulation. Vection is the illusion of self motion and is most often experienced when an observer views a large screen display containing a translating pattern. This illusion has only limited fidelity and duration unless it is reinforced by confirming vestibular information. Galvanic vestibular stimulation (GVS) can directly produce the sensation of vection.

A multi-degree-of-freedom (DOF) ultrasonic motor can rotate in three DOFs and does not generate noise. In addition, with an appropriate preloading mechanism, it can generate high torque for its size. The multi-DOF ultrasonic motor is, therefore, anticipated for use as a servomotor in the next generation of robots. However, for several reasons, there have been few applications of multi-DOF ultrasonic motors. One reason is the difficulty in designing a proper preloading mechanism for the motor and the limitation of the size of the stators. Another is the difficulty in developing a control algorithm, due to the motor's complex and changing dynamical characteristics, and the serious jaggy motion caused by its very quick response. This paper proposes a preloading mechanism and control algorithm for a multi-DOF ultrasonic motor, considering the motor's application to an actual auditory tele-existence robot, TeleHead. TeleHead is an elaborate dummy head robot that has a 3-DOF neck mechanism. The proposed methods achieve smooth and fast multi-DOF rotating motion of the dummy head with little time delay. In the preloading method, tensioned springs generate high preloading force and make up for the lack of torque by compensating for the resistance torque generated by the inclining motion of the dummy head. In the control algorithm, high-DOF motion is managed by high-frequency switching of the rotating axis, and smooth and quick trajectory tracking motion is achieved by introducing feed-forward control using an inverse model, with multiresolution acquired by feedback-error learning. Experimental results verify the high performance of these methods.

A multi degree of freedom (DOF) ultrasonic motor can rotate in three degrees of freedom and does not generate noise. In addition, it generates high torque with an appropriate pre-loading mechanism. This motor is therefore anticipated for use as a servomotor in robots in the next generation. This paper proposes a pre-loading mechanism and control algorithm for the multi-DOF ultrasonic motor for its application to an actual auditory tele-existence robot, TeleHead. The proposed methods realize fast multi-DOF rotating motion with little time delay. The pre-loading method generates pre-loading force by using tensioned springs, and compensates for the torque generated by the weight load on the motor by using these springs and a counter weight. The control algorithm uses feed forward control based on online feedback error learning. Experimental results show the high performance of these proposed methods.

Screw's are very widely used in a variety of machines because of their ease of use and very high joint force. However, the cross- or minus- shaped recess on the head of a screw causes a lot of problems. First, the recess can make a machine less aesthetically pleasing. Second, many screwdrivers of different diameter have to be available. Third, if the recess is damaged by a screwdriver, it becomes difficult or impossible to tighten or loosen the screw. In order to solve these problems, this paper proposes the recessless screws. The proposed screwdriver uses piezo electric cells to rotate recessless screws. The piezo-electric cells vibrate at ultrasonic frequency, and the vibration generates tightening torque. The principle of the proposed screwdriver is examined by experiments.