Kazunori Kaede

Study on Estimation of Driver’s State During Automatic Driving Using Seat Pressure

The development of an automatic driving system is accompanied by the increasing importance of driver monitoring. It is necessary to estimate the state of the driver including actions with less load on the driver. In this study, we used the seat pressure as an indicator to assess the status of a driver. In the experiment, we measured the seat pressure during automatic operation under the designated state (forward gaze, cell phone use and sleeping) of the driver. Characteristic changes in the center of gravity position of the driver were confirmed during cell phone use and sleeping. Subsequently, we evaluated seating surface pressure data by calculating the accuracy of state estimation using machine learning. The results show that the accuracy of estimation corresponded to 76.8% in the overall evaluation. This suggests that it is possible to estimate the state of the driver during automatic driving using seat pressure.

Evaluation of Legibility and Visual Fatigue Caused by Luminescent Text Displays

Light-emitting diodes (LEDs) are widely used for backlighting text indicators in vehicles. It is desirable that such text indicators have high legibility and low fatigue-inducing qualities. Suitable spectral distributions for text presentation in vehicles have not yet been clarified. This study examined legibility and fatigue when participants read Japanese sentences presented through backlight emission for 10 min in a dark room. The backlight indicators employed four type of white LEDs. The participants were asked to answer questionnaires to evaluate legibility and fatigue. Moreover, the critical fusion frequency and brain activity were measured to evaluate fatigue objectively. The questionnaire results show that all colored backlighting displayed almost an equal legibility. The overall result suggests that participants were most and least fatigued when viewing text illuminated by high color-rending and greenish white backlighting, respectively. Thus, fatigue can be reduced using LEDs with different spectral distributions.

Influence of VR-Based Slope Images on Walking Pattern

In this paper, we proposed a walking training system in which a trainee walks on a treadmill while viewing virtual reality (VR) images using head mounted display (HMD) for the purpose of developing a more continuous and effective walking training. Furthermore, the walking patterns when walking on the treadmill while viewing VR images of walking on a slope and level ground were determined and compared. Consequently, the braking force when viewing a VR image that walking on a downward slope was larger than when walking without viewing a VR image. Therefore, the same tendency as walking on an actual downward slope was obtained when subjects walked while viewing a downward slope image, and it was shown that the walking pattern can be changed by the proposed walking training system.

Examination of the Brain Areas Related to Cognitive Performance During the Stroop Task Using Deep Neural Network

To examine brain areas related to the cognitive load condition during the Stroop task, we proposed a method using a Deep Neural Network (DNN). We acquired cerebral blood flow data in congruent and incongruent tasks by near-infrared spectroscopy (NIRS) equipped with 22 ch. The data were used to train a DNN, and the influence of each factor on the output was evaluated. Our DNN model consists of independent input layers for each channel of NIRS, as well as fully-connected hidden layers and output layers. Our results suggest that the medial prefrontal cortex (focusing on cognition) and the left inferior frontal gyrus (focusing on language processing) were involved in the cognitive load during the Stroop task. These results in the Stroop task were consistent. Therefore, the proposed method’s utility was confirmed.

Evaluation of the Effect of the Amount of Information on Cognitive Load by Using a Physiological Index and the Stroop Task

There have been several recent attempts to aid car drivers by providing information on internal and external car environments. The optimal amount of information must be determined to avoid confusion. In this study, the “Stroop task” was used for information processing, and the cognitive load was gradually increased by adding information in stages. We designed and conducted two tasks that originate in the “Stroop task”; these two tasks feature significant differences in cognitive load. We also measured brain activity using near-infrared spectroscopy (NIRS) under the assumption that such activity can be used as an index of cognitive load. Both tasks were associated with increased oxy-hemoglobin levels in the prefrontal area, and the task with a higher cognitive load was associated with a more substantial increase in oxy-hemoglobin; this indicates that oxy-hemoglobin levels may be used as an objective index for the evaluation of information-associated cognitive load.

Haptic Feedback System Using Informative Resisting Torque for Lever Joystick Operation

Elderly adults show an aging-related decrease in hand dexterity. Hence, there is a need to develop techniques to address this impairment in manual dexterity, especially when the elderly operate equipment such as powered wheelchairs. In this research, we built and tested a prototype of a manual controlled input lever with two degrees of freedom. The system uses magnetic particle brakes in each rotational joint. The drag torque was implemented by actuation of the magnetic particle brake. In order to help control the input to a control system, the lever generates a resisting torque against the user’s actions at a suitable angle. The purpose of the proposed system is to reduce the burden of operation on the user while respecting their intentions. We confirm that this system is able to allow lever manipulation while avoiding inappropriate operation. The results of this study enable control input devices to adapt to the ability and preferences of the user.

Experimental Study on Color Preference and Visual Fatigue Against LED Lighting

In recent times, light-emitting diode (LED) lighting has been widespread in offices and manufacturing buildings, but for assembly operation in manufacturing situations, it has not yet been explored. In this study, we measure color preference and visual fatigue to evaluate LED task lighting for assembly operation. We conducted an experiment to obtain subjective responses to color preference and to measure visual fatigue under LED lighting. The participants were asked to assemble a gearbox model as a task under three different lighting conditions. As a result, lighting with high color temperature was rated with high visibility, fatigability, and low preference. On the other hand, critical fusion frequency, which indicates visual fatigue, was higher in lighting with low color temperature than in lighting with other conditions. This indicates that color preference as a subjective response discords from visual fatigue evaluated by biological information.

1311 Psychological Verification Based on Positive and Negative Affect and Measurement of Brain Activities while Watching Emotional Film Scenes

It is desired the method to analyze ordinary citizens mental state and transition at social various situations, and the business applicability using that is expected. In Europe, the FilmStim database which can arouse specific emotion was edited. In this study, we examined whether the FilmStim can be applied to Japanese. And we investigated the relationship between brain activity and positive and negative emotion by using NIRS. It was indicated the possibility that the emotional score of European can apply to Japanese by explaining contents of film. When arousing positive and negative emotion, it was indicated that oxyHb was changed at outer part of right brain. This result suggests that measuring brain activities can be used to distinguish whether positive or negative emotion is experienced.

Analysis of Brain Activity during VR-Based Driving Using Near-Infrared Spectroscopy

Driving assist systems, which are based on biological information, have been investigated in recent years. In this paper, we measured brain activity during simulated driving using near-infrared spectroscopy. Driving is a complex behavior that requires multiple cognitive elements. Therefore, we conducted two experiments to monitor driving behavior in an unvarying road environment and a road environment including an intersection. In the first experiment, the concentration of oxygenated hemoglobin (oxy-Hb) in the prefrontal cortex changed slightly during driving in an unvarying road environment. However, oxy-Hb in the prefrontal cortex increased significantly in a situation in which the subject was unsettled by unexpected vehicle behavior. In the second experiment, oxy-Hb decreased in the prefrontal cortex during driving that required more in-depth thinking, and this decrease in oxy-Hb was associated with the complexity of thinking. Our results demonstrate that the depth of thinking during driving is responsible for changes in oxy-Hb concentration in the prefrontal cortex.

A Near-Infrared Spectroscopy Study of Horizontal Vibration and Comfortableness of a Ride

Comfortableness of a ride is an important issue to passengers and drivers in an automobile. It is difficult to quantify comfortableness of a ride because it is affected by the rider’s emotions and physiology. In this paper, we measure brain activity using near-infrared spectroscopy (NIRS) to examine the features of brain activity that occur when a person is feeling vibration. The results obtained in this study may be used to quantify subjective evaluations of comfortableness of a ride. We measured brain activity during vibrations that are uncomfortable and during vibrations that are not uncomfortable. Uncomfortable vibration and vibrations that were not uncomfortable were determined based on sensory evaluations. Results reveal that oxygenated hemoglobin (oxy-Hb) levels in the prefrontal cortex change when feeling vibration. With uncomfortable vibration oxy-Hb levels declined more than with vibration that was not uncomfortable. In addition, we measured brain activity of riders feeling vibration which evaluation vary among subjects. We found that oxy-Hb of the subjects that feel uncomfortable vibration declined in the prefrontal cortex. Therefore, we inferred that the decline of oxy-Hb in the prefrontal cortex is related to feelings of discomfort.Copyright