Wyniki wyszukiwania - BazTech

1

Improvement of performance of Japanese P300 speller by using second display

Yamamoto Y., Yoshikawa T., Furuhashi T.

Journal of Artificial Intelligence and Soft Computing Research

|

2015

|

Vol. 5, No. 3

221--226

EN

Brain computer interface (BCI) is a system allows a user to control external devices or to communicate with other people using only his or her thoughts. The P300 speller is one such BCI in which users input letters. For inputting letters via the P300 speller, higher accuracy and shorter input times are needed, especially given densely populated display screens. We propose a new interface with a second display in the P300 speller that the user can switch to and from by selecting the “next” or “back” commands, therby reducing the density of displayed letters and improving the performance of the P300 speller. We show the comparison results in terms of accuracy and input times between the conventional interface and proposed interface.

2

Investigation of the temporal change of the sources of Aeolian dust delivered to East Asia using electron spin resonance signals in quartz

Yamamoto Y., Toyoda S., Nagasima K., Igarashi Y., Tada R.

Geochronometria

|

2013

|

Vol. 40, no. 4

355--359

EN

The temporal change in the number of oxygen vacancies in quartz was investigated by observing the E1’ center in the atmospheric depositions collected at two cities in Japan in the recent past. The depositions collected at Fukuoka in March show the ESR intensities being correlated with the sum of the number of the days, in the month, on which Kosa was observed while no such correlation was found in the deposition those collected at Akita but a trend of decrease with time. The present results suggest that the number of oxygen vacancies in quartz might be useful to estimate quantitatively the contribution of the dust originated from China to the atmospheric deposition in Japan.

3

The grain size influence on the E1'centre observed in quartz of atmospheric deposition at two Japanese cities : a preliminary study

Yamamoto Y., Toyoda S., Nagasima K., Igarashi Y., Tada R.

Geochronometria

|

2010

|

Vol. 37

9-12

EN

The grain size influence on the number of oxygen vacancies in quartz was investigated by ESR in atmospheric deposition collected at two Japanese cities, Fukuoka and Akita, in 1969 and 1971. The finer grain size fraction shows the highest value of concentration of oxygen vacancies, most closely resembling dust originating in the Taklamakan desert. Month to month and year to year variation of the dependence was also observed which could possibly be attributed to the variation of the mixture ratio of at least two dust sources in China, A conclusive statement can not be made at this stage.

4

Analysis of effect of radiation exposure on cultured cells using electrical cell-substrate impedance Sensing (ECIS) method

Goda N., Yamamoto Y., Nakamura M., Maruyama T., Kusuhara T., Mohri S., Kataoka N., Kajiya F.

Biocybernetics and Biomedical Engineering

|

2007

|

Vol. 27, no. 1-2

227-236

EN

A mathematical model for the micro-dynamics of cultured cells measured with the ECIS (Electrical Cell-substrate Impedance Sensing) system that can separately evaluate the cell-to-cell distance and the cell-to-substrate distance is proposed. For wide applications of this method, mathematical models considering various types of cells and confluent conditions were constructed. Using ECIS TM, frequency the characteristics of 25 Hz to 60 kHz of impedance of HUVEC (human umbilical vein endothelial cells), BAEC (bovine aortic endothelial cells), in the pre-confluent condition and the full confluent condition of each cell were measured. A mathematical model of the micro-dynamics of the cultured cells measured with ECIS from 1 kHz to 10 kHz, which was the most interesting frequency range for the micro-dynamic analysis in the ECIS methods is proposed. The evaluation method of the cell-to-cell distance (A) and the cell-to-substrate distance (h) could be improved. In the application, we investigated the effect of the X-ray radiation exposure from 1 Gy to 100 Gy on the cultured cells BAEC using the ECIS system. Impedance changes could be confirmed by exposure to 100 Gy. The X-ray stimulation of 100 Gy resulted in a significant increase of the value of the cell-to-cell distance (A).

5

Development of implantable assist pump and its peripheral devices

Okamoto E., Makino T., Yamamoto Y., Asao H., Watanabe N., Nakamura M., Tanaka S., Inoue Y., Yasuda T., Mitamura Y.

Biocybernetics and Biomedical Engineering

|

2006

|

Vol. 26, no. 1

45-51

EN

Two national project for development of an artificial heart system are being undertaken in Japan, and Hokkaido Tokai University has taken part in both national projects in order to develop peripheral devices of an implantable VAD (ventricular assist device) system. Each of the peripheral devices incIudes a transcutaneous energy transmission system, an internal battery system, and a transcutaneous information transmission system. Maximum energy transmission efficiency of the transcutaneous energy transmission system is over 85% (DC to DC) at an energy transmission ratio of 25 W. The internal battery system mainly consists of three lithium ion batteries, a charge circuit, and a power interface (case size of 11Ox80x30 mm). The internal battery system can drive a VAD for over 2 hours with maximum battery case surface temperature of 43°C. The information transmission system (diameter of 52 mm and thickness of 12 mm) mainly consists of an ASK modulator and an ASK demodulator employing carrier frequencies of 4 MHz and 10 MHz. It can transmit data electromagnetically between inside and outside of the body bi-directionally at a data transmission ratio of 56 kbps. Long-term animal experiments showed that each peripheral device has adequate performance to support the operation of implantable VAD.

6

Impedance pharyngography for diagnosis of swallowing disorders

Yamamoto Y., Nakamura T., Kusuhara T., Mori K.

Biocybernetics and Biomedical Engineering

|

2002

|

Vol. 22, no. 4

97-103

EN

Swallowing disorders are a serious problem occurring in association with cerebrovascular disorder, nerve or muscle disease, laryngeal or esophageal disease, or advanced age. Unfortunately, it is difficult to evaluate swallowing disorders quantitatively. For this reason, we previously proposed a new method, impedance pharyngography (IPG), for evaluating swallowing disorders noninvasively by measuring neck electrical impedance during swallowing. In this study, the efficacy of this method was tested in a cohort of patients with IPG and healthy controls. The change of neck electrical impedance in the pharyngeal phase is mainly caused by the changes in the equivalent cross-sectional area of the near epiglottis. In addition, the increase in equivalent cross-sectional area due to raising of the larynx caused a decrease in neck electrical impedance in the pharyngeal phase. In the case of healthy subjects, IPG results were highly reproducible, and the patterns were simple and similar. In subjects with advanced age, IPG are delayed-action, slowly changing and less reproducible, and showed various patterns among the subjects. In subjects with swallowing disorders, IPG results were less reproducible and showed irregular variable patterns. We therefore conclude that the IPG pattern can be used effectively as a simple index of swallowing activity.

7

Visualization of cubic (one-way, three-mode) dissimilarity data by using multidimensional scaling

Yadohisa H., Yamamoto Y.

Machine Graphics and Vision

|

2000

|

Vol. 9, No. 1/2

243-249

EN

A visualization method for cubic (one-way, three-mode) dissimilarity data is proposed. By using the framework of multidimensional scaling (MDS), the data are representated as points in a euclidean space. Two model to explain the data are proposed, and estimates are made by the alternating least squares method.

8

Influence of oxygen and humidity in atmospheres on friction and wear characteristics of TiN and TiC

Yang L., Yamamoto Y., Hashimoto M.

Applied Mechanics and Engineering

|

1999

|

Vol. 4, no spec.

195-200

EN

The friction and wear characteristics of hot pressed TiN and TiC were examined in dry and wet atmospheres of oxygen and argon using a pin/disc type friction tester. In an atmosphere containing oxygen or humidity, for both TiN and TiC, a surface film composed mainly of titanium oxides and/or their hydrates were produced during runs. The formation of the surface films resulted in suppressing brittle fracture of the rubbing surfaces and reducing wear amount by a factor of 4 to 30. TiC has high ability to form TiO2 with low shear strength compared to TiN. In contrast, TiN is expected to keep a TiO2 film firmly through TiO formed on the TiN surface as the substrate of TiO2, since a lattice constant and interatomic distances of TiN are nearly equal to those of TiO. Therefore, a low friction of about 0.1 was attained with a combination of TiC pins and TiN disc.