Kazuaki Goshi

An intelligent tutoring system for teaching and learning Hoare logic

Significant areas of the computer science curriculum are constantly and rapidly changing as new technologies (e.g., multimedia, WWW, Java) are adopted. This presents a challenge to our current education system: Intelligent Tutoring Systems (ITSs) for teaching and learning in Computer Science must be able to assist not only their student users but also the teachers in developing and managing courses to the best advantage of the students. We developed an ITS for teaching and learning Hoare logic. In this paper, we describe the practical use of the system in a computation theory course.

Effect of overlap rate between stereoscopic images on performance in a teleoperation

According to the results of the simulated teleoperation experiment, the larger the ratio of the overlapping area of stereoscopic images, the smaller the completion times and the number of errors. For this paper we did an experiment using the actual stereoscopic video system. We examined the performance of the teleoperation of an insert task in two experiments. In experiment 1, we set three fixed overlap rate conditions for the stereoscopic image pairs. (High overlap rate condition): The convergence point of the two cameras was set at the goal point where a cylindrical object was inserted. When subjects fixated their eyes on the goal point, the overlap rate of the images from the cameras was 95%. (Middle overlap rate condition): The convergence point of the cameras was set at the center of the working area. When subjects fixated their eyes on the goal points, it was 76.7%. (Low overlap rate condition): Convergence point of the camera was set at the point in the situation where the ratio of the overlapped area was 49% when subjects fixated to the goal point. Completion times and the numbers of errors of the insert task were measured. As a result, these were smallest at the high overlap rate condition. In experiment 2, we compared the performance between a fixed and a variable overlap rate conditions in a pick-and-insert task. The experimental results suggested that the number of errors of variable overlap rate condition was less than that of the fixed condition although the completion time of the former condition was not shorter than that of the latter condition.

Stereoscopic video system with embedded high spatial resolution images using two channels for transmission

Teleoperation requires both wide vision to recognize a whole workspace and fine vision to recognize the precise structure of objects which an operator wants to see. In order to achieve high operational efficiency in teleoperation, we have developed the Q stereoscopic video system which is constructed of four sets of video cameras and monitors. It requires four video channels to transmit video signals. However, four channels are not always available for a video system because of the limitation of the number of radio channels when multiple systems are used at the same time. Therefore we have tried to reduce the number of channels on this system by sending images from the right and left cameras alternately by field. In experiment 1, we compared the acuity of depth perception under three kinds of stereoscopic video systems, the original Q stereoscopic video system, the Q stereoscopic video system with two channel transmission, and the conventional stereoscopic video system. As the result of the experiment, the original Q stereoscopic video system enabled us to perceive depth most precisely, the Q stereoscopic video system with two channel transmission less so, and the conventional stereoscopic video system even less. In experiment 2, we compared the Q stereoscopic video system with two channel transmission to the original Q stereoscopic video system. The result showed that the operators were able to work more efficiently under the original Q stereoscopic video system than under the Q stereoscopic video system with two channel transmissions. In experiment 3, we compared the Q stereoscopic video system with two channel transmission to the conventional stereoscopic video system. It was found out in this study that the new stereoscopic video system we developed enabled operators to work more efficiently and to perceive depth more precisely than the conventional stereoscopic video system, although the number of channels for image transmission of this system was equal to that of the conventional stereoscopic video system.

Digital stereoscopic video system with embedded high resolution images

We developed a stereoscopic video system, which has high-resolution images for central vision and it is called the Q system. The Q system uses a compound image that is a wide-angle image with an embedded high-resolution image. However, the Q system could not be used under situations where many robots work at the same time. This is because it needs four channels of video signals and the available channels could be limited under such situations. Thus, we have developed a digital Q system. The system can be used under such restricted situations, because the required data transfer rate is adjustable by changing the compression rates for a high-resolution image and a wide-angle image. In addition, an experiment confirmed that even though the systems used the same data transfer rate, digital Q system could make teleoperation more efficient and more precise than a conventional stereoscopic video system.

Influence of Attention on the Control of Speed and Steering in Older Drivers and Stroke Patients

Objective: Attention is important for driving an automobile. The aim of this study was to identify driving behaviors that are influenced by attention. Methods: This study included 49 healthy individuals (19 men and 30 women) and 10 stroke patients (8 men and 2 women). The subjects’ attention was assessed using the Trail Making Test and the Simple Reaction Time task of the Continuous Performance Test. In a driving simulator with driving conditions set in accordance with the traffic regulations in Japan, including two lanes on each side of the road and a speed limit of 60 km/h, the subjects performed four left turn tasks, six right turn tasks, and six changing lane tasks. Road edge excursion frequency, speeding frequency and duration, crash frequency, speed during driving, distance from the vehicle ahead after entering the passing lane, vehicle positioning, and braking reaction time for a suddenly crossing vehicle were recorded. Results: The results showed that attention deteriorated in the older subjects and that this affected driving behaviors, particularly for staying in one´s lane. We identified the characteristics of driving behaviors during right and left turns as well as changing lane. Elder subjects delayed corrections of steering and the control of speed. Conclusion: In this driving simulator study, deterioration of attention in older drivers was related to road edge excursion and a delay in the control of speed and steering required for responding to the external environment under changing traffic conditions. It would be predicted the characteristics of the driving behavior by evaluating the attention. Although driving behaviors were similar for the stroke patients and the healthy subjects, stroke patients´ attention while driving requires a more detailed evaluation.

Effect of overlap rate between a stereoscopic image pair on work performance in VR environment

We did a tracking experiment in the virtual space to investigate the effect of an overlap rate between right and left images of a stereoscopic image pair on work performance. Twelve subjects tried to track a target moving around in a three-dimensional virtual space by the cursor that they controlled with a 3-D mouse. The high overlap rate condition was 100% overlapped and the low overlap rate condition was 50% overlapped. The convergence point of the virtual video cameras was fixed during the experiment. We measured the difference of the position between the target and the cursor in horizontal, vertical, and depth axes. The results showed: (1) the difference between the target and the cursor in the low overlap rate condition was larger than that in the high overlap rate condition; (2) the difference in depth was larger than these in horizontal and vertical axes; (3) the difference in depth occurred when the target moved far away from the subjects.

Relationship between operational efficiency and field-refreshing rates of stereoscopic image-pairs in teleoperational work

Most teleoperations require both wide vision for work space recognition and fine vision for the recognition of the object structure. To achieve a high operational efficiency in teleoperations, we developed the Q stereoscopic video system which was constructed by four video sets. Therefore, it requires for video channels to transmit video signals. However, four channels are not always free for the video system. Presently, only six wireless channels are assigned for controlling the machines at Japanese construction sites. To reduce the number of channels for video images, we tried to send the images from two cameras in a single channel alternatively. It was not clear how many field-refreshing rates of video images were necessary for teleoperations. We researched the relationship between operational efficiency and the number of field-refreshing rates per second. In the experiment, subjects were required to pick a cylindrical object up and insert it into a hole by operating a tele-robot under stereoscopic images in 60 Hz and 30 Hz field-refreshing rates. The results showed no significant differences between the two conditions in the completion time and the number of errors. Therefore, it is possible to reduce the field- refreshing rates by half, and provide two channels the Q stereoscopic video system without reducing the operational efficiency.