Environmental regulations such as RoHS are essential considerations in industry, however, it is almost not considered in technology education in secondary schools although the Courses of Study refers the relationship between the technology and both society and the environment. Also, designing an electrical or an electronic circuits in secondary school are very difficult compared to wooden products due to students' limited skills in electricity and difficulties of various parts preparation. In this paper, we report trial results for lead-free soldering and “design & production” study of an LED light in secondary schools. Both trials are carried out successfully so that these can be applied to standard learning materials in technology education.
Autonomous driving technologies have dramatically progressed these years. One of the challenges to autonomous driving is disengagement caused by unexpected situations such as occurrences of construction sites, passing of emergency vehicles. In case of disengagements, autonomous vehicles with no driver stall and prevent passage of the other vehicles. Remote driving is proposed to resolve stall of autonomous vehicle because of disengagement and can make recovery time of a disengaged autonomous vehicle shorter than the other approaches such as roadside assistance service. In this paper, we propose driving support information display scheme to improve safety in remote driving with delayed cellular communication. In the proposed scheme, an oncoming trajectory and a vehicle speed are displayed on the video sent from the on-vehicle camera for remote driving. We prototyped the remote driving system which was implemented the proposed scheme, and evaluated the effectiveness of the proposed scheme.
In this study, an Indoor MEssaging System (IMES) was used to determine walking positions in an indoor situation at rates of 50 and 250 bps in a ship, transmitting powers of -65 and -85 dBm. And furthermore, BLE (Bluetooth Low Energy) beacon and Wireless LAN (Wifi) access point were used to. The results confirm that the best tracking of pedestrians in an indoor situation is achieved using IMES with a transmitting in a ship. The results of these experiments will be of use for new IMES/GNSS chip set designs.
This paper proposes a virtual stamp rally system called Ugosta, and also describes the actual achievements of its prototype. A virtual stamp rally is an activity that the avatar of a player visits several places in a virtual world and collect the imprints of stamps placed there. Ugosta is a system that provides an environment where a user plays a virtual stamp rally seeing scenery images of various points on the earth in conjunction with the operation of an exercise equipment such as an exercise bike or a treadmill. It is currently being developed in order to promote adherence of exercise that uses such an equipment. In this kind of exercise, some users feel not only sense of accomplishment, but also sense of boredom. Ugosta uses a virtual stamp rally to increase sense of accomplishment, and uses scenery images to decrease sense of boredom. The prototype of the system has been displayed in a lot of exhibitions and actual scenes, and the favorable reviews for it has been gotten from many participants.
Vestigial remnant of surgical instruments in the body is a serious problem. Two dimensional symbol is being used to help manage this problem. However, the symbols have to be identified one at a time, since the symbols are a sort of printed matter. An HF band passive RFID was also proposed. This system also had problems in identifying the signals of a large number of surgical instruments in bulk, since the scope of its identification area was relatively small. To improve the deficiencies of this system, a UHF band passive RFID system was developed. A new low-intensity antennae are also proposed for the UHF band passive RFID system. From experimental results, 50 surgical instruments were identified in less than one second with this new RFID system. This new system will undoubtedly reduce the workload of surgical nurses, while reducing human error in the operating room.
Spatio-temporal patterns of neural activities develop repeatability, diversity, and hierarchy. In the present study, we attempted to elucidate how these dynamical properties are associated with a network structure in primary cultures of dissociated neurons. High-density CMOS electrode array investigated spatio-temporal activity patterns of dissociate neuronal cultures throughout development. Additionally, based on the spatio-temporal patterns in each test culture, a structure of functional network was estimated with transfer entropy in a pairwise manner. Consequently, repeatability increased with connection strength, dispersity, and clustering at the early developmental stage. Subsequently, hierarchy developed with connection strength and dispersity. These results demonstrated that a repertoire of activity patterns developed with some characteristics of network structure.
Cortical dipole imaging has been developed to visualize brain electrical activity in high spatial resolution. In this method, it is necessary to solve an inverse problem to estimate the cortical dipole distribution from the scalp potentials. In the present study, we focused on the filtering property of the spatial inverse filter. We aimed to visualize the signal pathways by applying an inverse function. We proposed a sigmoid function-based inverse filter and compared with the traditional inverse techniques such as Tikhonov regularization, truncated singular value decomposition (TSVD), and truncated total least squares (TTLS), in a computer simulation. The proposed method was applied to actual human electroencephalogram to the visual evoked potential. We confirmed that the signal was localized to a location consistent with physiological findings. Moreover, the pathway of visual information was visualized by cortical dipole distribution.
This study is to examine EEG frequency components relating the intention (“I want to drink”) to “with/without speech imagery” when drink-images are displayed on the PC screen. An experimental process was set in 8 s as followings; fixation image display (1 s), drink image display (2.5 s), intention check (1.5 s), fixation image display (1 s), and speech imagery period (2 s). It was repeated 100 times. EEG was measured with 10-20 system in a magnetically shielded room with BPF (0.08-100 Hz) and notch filter (50 Hz) for 10 subjects. In the analysis, it was averaged with 35 trials dividing between “with/without speech imagery” in an epoch (fixation image display and speech imagery) of 3 s and time-frequency analysis was done. Event-related synchronization (ERS) and desynchronization (ERD) were examined with t-test. ERS were observed in α-band on the left-hemisphere in case of “with speech imagery” for latency of 500-1500 ms and the significant differences (p<0.05) were shown in the left-hemisphere and occipital-region. It is suggested the useful information of selecting electrode positions to detect EEG frequency components for judgment of “with/without speech imagery” in the intention. In addition, an examination to localize electrode was conducted. As a result, it is suggested that averaged RMS value for each frequency component gives useful information even when localized to 9 electrodes.
Estimating current states of neuronal networks from multi-neuron measurement helps a brain-machine interface to replace lost brain functions. Estimating brain states based on a physiological model has a huge advantage on estimation accuracy and directness to biophysical phenomenon. In this study, we propose a model-based method for accurate synaptic connection estimation with short time delay. The method merges our previous method and Song's spike-timing-dependent plasticity rule using Kalman filter to utilize past estimation data by assuming prediction rules. The proposed method achieved an accurate estimation by 5 s of recorded data, while previous method required > 20 s. Then, it was examined if the method can detect stimulation-induced plasticity in living neuronal network, using rat cortex neurons cultured on a microelectrode array. The proposed method detected synaptic plasticity immediately after induction. These results suggest that our method is suitable for estimating synaptic connection strength accurately with a short time delay.
VideoEndoscopy (VE) and VideoFluorography (VF) are the classic inspection methods used for evaluating the function of swallowing, but are disadvantageous in that they are invasive. Therefore, we have proposed a noninvasive method that uses pharyngeal ultrasound videos to estimate the internal flow characteristics of foods and evaluates the swallowing function level quantitatively. We are proposing a new method that combines optical flow with Maximally Stable Extremal Regions (MSER) to extract the movement velocity and position of esophagus and bolus. The results showed that the movement velocity could be used as an indicator to quantify the internal flow characteristics of foods. The displacement of the esophagus indicates the esophageal opening; this could be used as an indicator to evaluate the swallowing. In this study, we confirmed that a classification of esophageal and bolus movements should be performed automatically by the developed method to decrease the evaluation time.
Epilepsy is a neurological disorder that occurs due to the abnormal electrical discharges in the brain, thus affecting the patient's personality, behavior and day-to-day routine. Epilepsy can be broadly classified into generalized epilepsy and focal epilepsy. Focal epilepsy occurs due to abnormal electrical discharges in the smaller section of the brain. These electrical discharges later spread to the larger part of the brain, resulting in generalized epilepsy. In this paper, a computer-aided diagnostic system is proposed to detect the focal epilepsy using electroencephalogram (EEG) signals. Features from the decomposed signals are extracted using fuzzy approximation entropy, Higuchi's fractal dimension and correlation dimension. Classification accuracy of 87.68% and 84.45% was obtained using K nearest neighbor (KNN) and support vector machine (SVM) classifiers respectively.
Electrophysiological data from in vivo and slice preparations show that inhibitory neurons had shorter duration action potentials (AP) than excitatory neurons. However, this criterion has not yet been established in dissociated cultured neurons. In the present study, we used a high-density CMOS microelectrode array to extracellularly investigate neural signals in primary dissociated cultures of rat neocortex, and we characterized AP waveforms to discriminate excitatory and inhibitory neurons. The CMOS array offers the possibility to acquire comprehensive spatio-temporal neural activity patterns with 11,011 electrodes in about 2×1.75 mm2 area at 20-kHz sampling rate. The waveforms of APs were investigated around cell bodies of neurons, which were classified into either excitatory neurons or inhibitory neurons on the basis of MAP2 and GABA immunostaining images. Consistent with previous in vivo and slice studies, we demonstrated that AP waveforms of inhibitory neurons had shorter durations and recovery time than those of excitatory neurons. The discrimination accuracy was around 0.9 in the receiver-operating characteristics (ROC) analyses. Additionally, taking advantage of non-invasive CMOS recording, we investigated AP waveforms throughout development of cultures. We confirmed that APs were classified into two classes, i.e., putative excitatory and inhibitory neurons, regardless of developmental stages, and found that the duration and recovery time of AP shortened in matured cultures. Thus, AP waveforms have rich information about cell types and developmental stages, which are of worth to elucidate underlying mechanisms of neuronal dynamics in spatio-temporal patterns.
We designed an experimental system to measure micro-electrocorticograms (µECoG) with 4×4 epi-dura electrodes implanted in the temporal cortex in a head-fix preparation of awake rats. During measurement, rats were allowed to pull a lever voluntarily, which was associated with delivery of water reward. With the setup, we trained rats to report conscious perception of tone and mapped the auditory evoked potentials (AEP) around the audible threshold. We demonstrated that conscious perception was associated with P3 wave rather than the middle latency AEP. Thus, our experimental setup was able to characterize µECoG during auditory tasks, opening a new avenue to investigate the neural correlates of consciousness.
A current-steering DAC is proposed to measure urinary bladder volume. The proposed DAC is composed of a 4-bit pull current DAC, a 4-bit push-pull current DAC, and a 2-bit push-pull current DAC. Since the output voltage range of three DACs is limited for the urinary bladder volume measurement, the resolution and power consumption of the DAC are reduced. The proposed DAC is evaluated by HSPICE simulation using 0.6 µm CMOS technology parameters. The DAC dissipates 241 µW with 5 V supply voltage.
This study developed a timer for bedsore prevention, which measured the elapsed time from the last body movement. The timer employed capacitively coupled electrodes to detect body movement. A change in the capacity due to body movement converted into a voltage change, which generated pulses to stop, reset and restart a timer. The validity of the developed timer was investigated through an experiment, in which body movement was simulated by hand movement. No error was occurred in 30 trials of the experiment, suggesting its validity.
A method for monitoring the degree of red blood cell aggregation by using an ultrasonic peak frequency is proposed. To demonstrate the effectiveness of the method, a technique for controlling the degree with a wide dynamic range was necessary. However, efficiently large aggregations could not be generated only by using flocculants for the red blood cells. In this study, we tried to create large aggregations under alkaline conditions, which are known as an aggregation-accelerating factor. We aimed to extend the dynamic range and evaluate the monitoring method.
Amyloid beta oligomer (ABO) is regarded to be a pathogenic factor for Alzheimer's disease (AD). Here, we aim to evaluate effects of ABO on synchronized activity of neuronal networks. Cortical neurons were cultured on microelectrode arrays, and spontaneous activity was recorded for 24 hours with ABO. Networks showed clustered- bursting activity for a few hours after ABO supplementation, and then periodic bursts. While firing rate of cultures with ABO gradually decreased, that of controls slightly increased. Results suggest that ABO damages neuronal networks by hyper excitation. Our system will be an effective tool for developing a novel treatment to AD.
We have developed RuO2 thin and thick films by photo-induced chemical solution process such as excimer laser-assisted metal organic deposition (ELAMOD) and photo reaction of hybrid solution (PRHS). In the case of using ELAMOD, resistivity of tie films was 5.8×10-4 Ωcm. Also, flexible RuO2 films on Polyimide was obtained by PRHS. In this paper, we describe the formation of RuO2 films and the preparation of flexible RuO2 films for SiC power devices.
Increasing the pulse current frequency from 0.5 kHz to 5 kHz suppressed the cracking of the Ni-W film. In addition, the film thickness increased from 15 µm to 20 µm. However, the W content of the Ni-W film was around 20 at% and was not affected by the frequency of the pulse current. In the resin mold, the Ni-W film was peeled off. However, Ni type was able to deposit Ni-W film of 78 µm thickness. However, pinholes occurred at the apex of the eye structure of the moth of the Ni-W mold. As a cause of the occurrence of pinholes, it is considered that the hydrogen generated during plating remains in the concave portion of the moth eye structure on the Ni master disk, so it is necessary to prevent hydrogen from remaining in the concave portion.
Fog-Cloud computing system has recently attracted much attention. This system has a simple three-tiered hierarchy: Network edge, Fog, and Cloud. Network edge includes IoT (Internet of Things) devices. Fog is localized computing facilities including network devices such as an edge router, a switch and any other. In this system, Fog handles various data processing, which are sensitive to delay, to shorten WAN propagation latency arising from the location of Cloud. However, if the data processing is concentrated on Fog, the delay of the processing and power consumption of the network edge may increase rather than Cloud computing. The reason why is because Fog has more limited resources than Cloud. Therefore, we should decide an appropriate allocation of roles between Fog and Cloud taking the latency of the processing and the power consumption of the network edge into account. In this paper, we consider the design of Fog-Cloud computing taking the latency and cost resulted from the power consumption into account by using a mixed integer linear programming.
Force-like sensations of fingers are evoked by vibro-tactile stimulation applied onto fingertips. This phenomenon is expected to be used for small and simple force displays, since the users wear only small vibrators on their fingertips. In this study, the properties of magnitude of the force-like sensations by vibration were investigated psychophysically, and the activities of finger muscles were measured by digital force gauge. As a result, it was found that the magnitude of force-like-sensation increases, as vibro-tactile stimulation increases.
In this paper, we present a new smart wheelchair which utilizes projection-based mixed reality techniques. The wheelchair enables a user to interact distant objects by user's hand directly. A touch-based MR interface allows the user to extend his/her hand and arm onto the real environment by projecting the user's hand graphics from an onboard projector, In order to realize the higher controllability of wheelchair motion, the unified touch gesture-based interface controls both the extended virtual hand and the electric wheelchair seamlessly. This paper introduces a feasible framework of touch control of wheelchair, control of extended body, learning-based automatic operation switching, and graphical representation of projected hand image. We confirmed the accuracy of operation switching and the suitable projection of the virtual hand through experiments.
Since solar power generation has increased rapidly, balancing function, especially in the form of increasing demand, is becoming needed. We proposed technique of active demand creation in previous study in which an aggregator dispatched home appliances expected to be IoT-ready in the near future in order to consume the surplus deriving from over-generation of solar energy.
In this study, we evaluate operating characteristics of PCS by experiment on active demand creation co-operated with solar power generation. In this experiment, our demand dispatch system implemented in previous study sends mitigated curtailment rate to existing PCS. Deference between demand creation characteristics and PCS output characteristics is discovered in the experiment and a solution to this challenge is proposed in this paper.