The purpose of this study was to examine the influence of comfortable walking on brain activity during a working memory task using multiple psychophysiological evaluations. We used the Roken Arousal Scale as a subjective evaluation, and electroencephalograms (alpha attenuation coefficient (AAC), θFz/αPz) and near-infrared spectroscopy (oxygenated hemoglobin) as physiological indices. AAC is an evaluation index of arousal level, and θFz/αPz is an evaluation index of concentration power. To determine the comfortable walking speed for each participant, we used a 10-m walking test. The oxygenated hemoglobin concentration, AAC, and θFz/αPz value tended to increase with walking at a comfortable speed at the time of the working memory task. In conclusion, when comfortably walking while performing a working memory task, the decrease in the brain's arousal level is suppressed, and working memory ability and concentration are maintained.

We performed subjective physiological assessment of brain activity using the visually performed n-back task and the n-back task performed by the auditory sense. The visually performed n-back task was done with two tasks that were performed while memorizing presented numbers and the result of computational problems. We characterized and compared the oxygenated hemoglobin concentration change in the brain during the working memory task using near-infrared spectroscopy measurement. Changes in activation of brain activity were observed due to differences in tasks. The difference in the presentation method resulted in a difference in activation of brain activity. Furthermore, the computational n-back task with execution function in working memory induced more brain activity than the usual n-back task. Thus, the computed n-back task is a suitable task to train workers.

The purpose of this study was to examine features of attention and concentration based on differences in the amount of unnecessary information using multiple psycho-physiological evaluations. We used the Roken Arousal Scale as a subjective evaluation, and electroencephalograms (alpha attenuation coefficient (AAC), P300) and near-infrared spectroscopy (oxygenated hemoglobin) as physiological indices. To investigate the psycho-physiological differences due to differences in the amount of unnecessary information, we used the oddball paradigm task. As the number of non-target stimuli increased, the oxygenated hemoglobin concentration increased and the P300 amplitude and AAC value tended to decrease. In conclusion, when the amount of unnecessary information is small, the load on the brain and arousal level of decrease are suppressed, and work can be performed while maintaining attention and concentration.

The purpose of this study was to investigate the effect of open versus closed eyes during a working memory task on physiological indices of workload. We used the NASA-TLX as a subjective evaluation, and electroencephalograms and oxygenated hemoglobin (oxyHb) concentrations measured via near-infrared spectroscopy as physiological indices of workload. Subjects performed n-back tasks while simultaneously performing an alpha attenuation test (eyes closed [30 s], eyes open [30 s] x 3) for 3 min. Increasing the task load increased the weighted workload and oxyHb. Since Fz / αPz in the open-eyes state shows the same trend as oxyHb, we were able to confirm that Fz / αPz in the open-eyes state is an index of the degree of the workload. However, Fz / αPz varied little between tasks or over time in the closed-eyes state. These results suggest that Fz / αPz is suitable as an index for indicating the degree of a workload only when the eyes are open.

The purpose of this study was to examine the physiological effects of respiratory control using vibration stimuli based on biological signals. We monitored changes in physiological indexes, the alpha attenuation coefficient (AAC), and area S of the Lorenz plot (LP-area-S), as objective parameters, and Roken Arousal Scale (RAS) and Visual Analogue Scale (VAS) scores as subjective parameters in participants performing mental or physical load tasks. Physiological index results showed decreased AAC and increased LP-area-S, while RAS results showed decreased tension and increased relaxation. These findings indicate that the respiratory cycle affects the autonomic and central nervous systems. In conclusion, we showed that short-period respiratory control alleviates physical fatigue and that longperiod respiratory control alleviates mental fatigue.

Advances in image processing mean it is now possible to measure heart rate variability (HRV) and respiratory rate without contact. The influence of mental workload and dual tasking on HRV and respiratory rate has not been well studied. The objective of the present study was to quantify the relations between workload and dual tasking and HRV and respiratory rate. We measured the weighted workload score of the NASA Task Load Index, the mean oxygenated hemoglobin (oxyHb) concentration, the standard deviation of oxyHb concentration, respiratory data and electrocardiogram data. Subjects performed n-back tasks, Stroop tasks and visual search tasks in low-and high-workload conditions and single-and dual-task conditions. Each task required different attention functions. Respiratory rate was significantly greater in the dual-task conditions than in the single-task conditions, indicating that divided attention increased respiratory rate. The NASA Task Load Index weighted workload score in the Stroop task was higher in the high-workload, dual-task condition than in the low-workload or single-task condition, and oxyHb concentration in the frontal area was lower. This indicates an overload state. In this condition, electrocardiogram data showed distinctive trends. For example, the high-frequency component of electrocardiogram data and mean RR interval were high in the high-workload, dual-task condition. These results suggest that attentional functions and overload in a dual task affected respiratory rate and HRV.

Recently, advances in stereoscopic imaging technology have provided new opportunities to view three-dimensional (3D) images. 3D imaging technology will likely be further utilized in medical facilities. In our study, we measured oxygenated hemoglobin (oxyHb) and the high-frequency component (HF) as objective parameters and the Roken Arousal Scale (RAS) and the Simulator Sickness Questionnaire (SSQ) as subjective parameters in experimental participants during the Multiple Object Tracking (MOT) task in 3D stereoscopic image conditions. The highest mean value of oxyHb change was recorded for the 3D-MOT task. In the 3D condition, HF values were significantly different between MOT and no MOT. Subjective evaluation of the RAS and SSQ results showed that general activation increased and disorientation decreased when experimental participants performed 3D-MOT. In summary, we found that the psycho-physiological responses of test subjects were affected by presentation conditions, and 3D-MOT decreased problems with 3D comprehension and led to brain activation.

The objective of this study was to monitor changes in physiological indexes of alpha attenuation coefficient (AAC), high-frequency component (HF) and oxygenated hemoglobin (oxyHb) as objective parameters and Roken Arousal Scale (RAS) as a subjective parameter in experimental participants performing simple tasks related to motor skills, as necessary for safe driving. The oxyHb signal was monitored from the frontal association and somatosensory areas using near-infrared spectroscopy (NIRS), which can measure changes in brain hemodynamics during tasks noninvasively and without constraint. Experimental results showed oxyHb and AAC increased, while HF and tracking error decreased when experimental participants were exposed to body sensory vibrations. From these findings, we suggest that body sensory vibration stimuli are valid for monotonous work. In conclusion, we showed the usability of body sensory vibration stimuli for monotonous work such as UniMove, with influences on the autonomic and central nervous systems.

Changes in skin temperature are known to be affected by blood flow. The reaction of skin temperature and blood flow when various stimuli are applied to the body has been investigated for many years. However, body reactions when different stimuli are applied concurrently to the body have not been well studied. This study investigated changes in blood flow and skin temperature when massage stimulation and thermal stimulation were applied to the body simultaneously. Skin temperature tended to change quickly when a massage stimulus was present during the task. In addition, the amount of blood flowing values were significantly higher and the speed of blood flow values tended to be higher during tasks with massage stimulus. Massage stimulation thus appears to significantly affect blood flow and accelerate changes in skin temperature from hot and cool stimulations.

We proposed a computer with low-level parallelism as one of the basic computer architectures and built a large scale experimental system called QA-2. By low-level parallelism, we mean that a long-word instruction controls simultaneously many ALUs, busses, registers and memories in a mode of fine-grained parallelism. The QA-2 employs a 256-bit instruction by which four different ALU operations, four memory accesses to different/continuous locations and one powerful sequence control are all specified and performed in parallel. If many simultaneously executable operations are detected and embedded in one instruction at compile time, this type of computer can provide a high-degree of performance for a wide variety of applications. This paper describes the architectural benefits and limitations of low-level parallelism in performing 3-D color image generation and interpreting Prolog/Lisp programs. The hardware organization with four ALUs, which are actually implemented in the QA-2, is verified to be adequate. In fact, nearly three out of four ALUs can work in parallel. Any architecture with more than four ALUs can not achieve a significant degree of performance enhancement. This paper also shows the degree of performance improvement achieved by the techniques such as ALU chaining and highly-structured sequence control mechanisms. As compared with the IBM 370 architecture, the QA-2 can generate 3-D color images in 1/5 of dynamic instruction steps. The compiler version of Prolog machine on the QA-2 is as fast (45K LIPS) as the ICOT's PSI. From all results, we expect that the QA-2 is a high-performance computer which will be utilized in the future personal computing environment.

This paper describes the hardware architecture and the employed algorithm of a parallel processor system for three-dimensional color graphics. The design goal of the system is to generate realistic images of three-dimensional environments on a raster-scan video display in real-time. In order to achieve this goal, the system is constructed as a two-level hierarchical multi-processor system which is particularly suited to incorporate scan-line algorithm for hidden surface elimination. The system consists of several Scan-Line Processors (SLPs), each of which controls several slave PiXel Processors (PXPs). The SLP prepares the specific data structure relevant to each scan line, while the PXP manipulates every pixel data in its own territory. Internal hardware structures of the SLP and the PXP are quite different, being designed for their dedicated tasks.

This paper describes the architecture of a dynamically microprogrammable computer with low-level parallelism, called QA-2, which is designed as a high-performance, local host computer for laboratory use. The architectural principle of the QA-2 is the marriage of high-speed, parallel processing capability offered by four powerful Arithmetic and Logic Units (ALUs) with architectural flexibility provided by large scale, dynamic user-microprogramming. By changing its writable control storage dynamically, the QA-2 can be tailored to a wide spectrum of research-oriented applications covering high-level language processing and real-time processing.

A machine-independent high-level microprogramming language, called MPGL, has been developed along with its processing system, called MPG. The MPGL allows the microprogrammer to write microprograms sequentially in a machine-independent fashion. The MPG provides the facility for translating these microprograms into efficient object code, as well as debugging object microprograms.

A new microprogrammable computer with low-level parallelism was built and has been utilized as a research vehicle for solving different classes of research-oriented applications such as real-time processings on static/dynamic images, pictures and signals, and emulations of both existing and virtual machines including high (intermediate) level language machines. The design goal of the machine was to achieve a high degree of processing enhancement in research- oriented applications by means of a low-level parallel processing organization combined with dynamically microprogrammable control. The machine has the capability to process multiple data streams, performing parallel operations with four 16-bit ALU's. These ALU's are independently controlled by the different fields of a 160-bit horizontal-type microinstruction, and have simultaneous access to 15 working registers. This microprogrammed MIMD organization is expected to provide a greater degree of flexibility for low-level parallel processing. In addition, not only does the machine contain powerful ALU's and a large number of registers, but also it employs flexible control structures and a hierarchical organization of control storage. All of these combine to yield extensive microprogramming capability which the user can effectively tailor to a wide spectrum of applications.