Motoyuki Akamatsu

Multimodal mouse: A mouse-type device with tactile and force display

A mouse was modified to add tactile and force display. Tactile feedback, or display, was added via a solenoid driving a small pin protruding through a hole in the mouse button. Force feedback was added via an electromagnet and an iron mouse pad. Both enhancements were embedded in the mouse casing, increasing its weight from 103 to 148 g. In a target selection task experiment, the addition of tactile information feedback reduced target selection times slightly, compared to the no additional feedback condition. A more pronounced effect was observed on the clicking time—the time to selection once the cursor entered the target. In this case, we observed a statistically significant speed-up of about 12% in the presence of tactile feedback. The modified mouse was also used in a test of virtual texture. The amplitude and frequency of solenoid pulses were varied according to the movement of the mouse and the underlying virtual texture. Subjects could reliably discriminate between different textures.

Movement characteristics using a mouse with tactile and force feedback

Abstract A multi-modal mouse incorporating tactile and force feedback was tested in a target selection task with 12 subjects. Four feedback conditions (normal, tactile, force, tactile+force) were combined with three target distances and three target sizes. We found significant reductions in the overall movement times and in the time to stop the cursor after entering the target. This effect was particularly pronounced for the tactile condition and for small targets. However, compared to normal feedback, error rates were higher with the tactile and tactile+force conditions. The motor-sensory bandwidth calculated using Fitts law, normalized for spatial variability, was highest in the presence of tactile feedback (6.4 bits/s). This was followed by tactile+force (6.2 bits/s), normal (5.9 bits /s), and force feedback (5.8 bits/s). These results indicate that modifying a mouse to include tactile feedback, and to a lesser extent, force feedback, offers performance advantages in target selection tasks.

Preparatory inhibition of cortico-spinal excitability: a transcranial magnetic stimulation study in man

In order to investigate the preparatory modulations of cortico-spinal excitability, reaction time (RT) methods were combined with transcranial magnetic stimulation (TMS) of the motor cortex. We analyzed the variations in the amplitude of motor potentials evoked in a prime mover (flexor digitorum sublimis) by TMS delivered during the foreperiod of a visual choice RT task. In experiment 1 (n = 10), the TMS was delivered either simultaneously with the warning signal or simultaneously with the response signal in two conditions of foreperiod duration: short (500 ms) and long (2500 ms). The peak amplitude of the motor evoked potentials diminished during the short foreperiod but not during the long foreperiod. Since RT was shorter when the foreperiod lasted 500 ms than when it lasted 2500 ms, this result suggests that the excitability of the cortico-spinal structures is minimal when the subject is optimally ready to react. In experiment 2 (n = 10), the time-course of this decrement was further explored. With this aim, only the short foreperiod was used and the TMS was delivered either 500 ms, 333 ms, 167 ms or 0 ms before the response signal. Cortico-spinal excitability decreased during the first 333 ms and then remained stable until the occurrence of the response signal. In light of previous studies, the present results suggest that the decrement of cortico-spinal excitability during the short foreperiod reflects an adaptative mechanism which increases the sensitivity of the motor structures to the forthcoming voluntary command.

Changes in applied force to a touchpad during pointing tasks

Abstract We measured the force applied to a touchpad during pointing tasks for large and small targets. A mouse was also used as a baseline condition. Our set-up to measure force included a Plexiglas plate mounted on a high-sensitivity three-axis strain gauge connected to an instrumentation amplifier and a data acquisition computer. The devices were positioned and operated on top of the plate with the selection button removed and actuated by the opposite hand. An experiment used 12 participants performing point-select tasks in conformance with ISO 9241-9. At the terminal phase of the selection tasks, the applied force with the touchpad was lower than that recorded with the mouse. These differences may be the source of overall performance differences between the two devices. It is suggested that the detected finger force should be a variable in the touchpads transfer function to afford a better blend of coarse and fine positioning strategies, with the goal being to bring the touchpad more inline with the mouse in overall user performance. Relevance to industry It reports measurements of applied force on the touchpad and mouse pointing devices; demonstrates different strategies employed by users in the final phase of cursor positioning in target selection tasks; presents opportunities to improve cursor positioning with touchpads through a transfer function optimized for the applied finger force on the pad surface.

Multineuronal spike classification based on multisite electrode recording, whole-waveform analysis, and hierarchical clustering

We proposed here a method of multineuronal spike classification based on multisite electrode recording, whole-waveform analysis, and hierarchical clustering for studying correlated activities of adjacent neurons in nervous systems. Multineuronal spikes were recorded with a multisite electrode placed in the hippocampal pyramidal cell layer of anesthetized rats. If the impedance of each electrode site is relatively low and the distance between electrode sites is sufficiently small, a spike generated by a neuron is simultaneously recorded at multielectrode sites with different amplitudes. The covariance between the spike waveform at each electrode site and a template was calculated as a damping factor due to the volume conduction of the spike from the neuron to the electrode site. Calculated damping factors were vectorized and analyzed by hierarchical clustering using a multidimensional statistical test. Since a cluster of damping vectors was shown to correspond to an antidromically identified neuron, spikes of different neurons are classified by referring to the distributions of damping vectors. Errors in damping vector calculation due to partially overlapping spikes were minimized by successively subtracting preceding spikes from raw data. Clustering errors due to complex spike bursts (i,e., spikes with variable amplitudes) were avoided by detecting such bursts and then using only the first spike of a burst for clustering. These special procedures produced better cluster separation than conventional methods, and enabled multiple neuronal spikes to be classified automatically. Waveforms of classified spikes were well superimposed. We concluded that this method is particularly useful for separating the activities of adjacent neurons that fire partially overlapping spikes and/or complex spike bursts.

Prediction of Human Driving Behavior Using Dynamic Bayesian Networks

This paper presents a method of predicting future human driving behavior under the condition that its resultant behavior and past observations are given. The proposed method makes use of a dynamic Bayesian network and the junction tree algorithm for probabilistic inference. The method is applied to behavior prediction for a vehicle assumed to stop at an intersection. Such a predictive system would facilitate warning and assistance to prevent dangerous activities, such as red-light violations, by allowing detection of a deviation from normal behavior.

Changes in spinal excitability during choice reaction time: The H reflex as a probe of information transmission

The aim of the present study was to investigate the modulations in amplitude of H reflexes elicited in a hand muscle, the flexor pollicis brevis, during the performance of a choice reaction time (RT) task in which this muscle was directly involved. Ten subjects were to choose between a left- or a right-thumb key-press according to the lateral location of a flash of light. The stimulus-response mapping was either compatible or incompatible. Hoffman reflexes were elicited at different times during the RT by stimulation of the median nerve. Twenty-five milliseconds before the voluntary response, the amplitude of the H reflex suddenly increased when the muscle was involved in the response and decreased symmetrically when the muscle was not involved in the response. Mapping compatibility exerted no detectable influence on the changes in spinal excitability. The latter result supports the assumptions that are at the core of Sternbergs additive factor method.

Automotive Technology and Human Factors Research: Past, Present, and Future

This paper reviews the history of automotive technology development and human factors research, largely by decade, since the inception of the automobile. The human factors aspects were classified into primary driving task aspects (controls, displays, and visibility), driver workspace (seating and packaging, vibration, comfort, and climate), driver’s condition (fatigue and impairment), crash injury, advanced driver-assistance systems, external communication access, and driving behavior. For each era, the paper describes the SAE and ISO standards developed, the major organizations and conferences established, the major news stories affecting vehicle safety, and the general social context. The paper ends with a discussion of what can be learned from this historical review and the major issues to be addressed. A major contribution of this paper is more than 180 references that represent the foundation of automotive human factors, which should be considered core knowledge and should be familiar to those in the profession.

Modeling of Driving Behavior When Approaching an Intersection Based on Measured Behavioral Data on An Actual Road

It is important to develop a driving assistance system that conforms to individual driving behavior. An individuals usual driving behavior is generally adapted to road and traffic situation; therefore, we propose that assistance be provided when that behavior deviates from normal. We developed specially equipped vehicles to collect natural behavioral data from repeated driving experiments on an actual road. We subsequently developed a Bayesian network model of occurrence of behavioral events from the data obtained when approaching a specific intersection with a stop sign. Any deviation from usual operation behavior can be estimated using this model. Unusual behavior can be regarded as inappropriate behavior and therefore its detection can be applied to driving assistance methods, such as warning presentation.

The influence of combined visual and tactile information on finger and eye movements during shape tracing

Adaptation experiments in shape tracing were conducted to investigate finger and eye movements in various conditions of visual and tactile information. Maximum velocity, mean velocity, maximum acceleration and reacceleration point were calculated from finger movements. Number of eye fixations and lead time of eye fixation to finger position were calculated from eye movements. The results showed that for the finger movement the values of the indices studied were higher in the combined visual and tactile condition than in the visual only condition. The number of eye fixations decreased when subjects repeated the tracing and was more marked in the combined visual and tactile condition than in the visual only condition. The results suggest that finger movements become faster and use of vision is reduced when both visual and tactile information are given.