An efficiency of interactive differential evolution for optimization of warning sound with reflecting individual preference

Interactive evolutionary computation (IEC) is a method for creating media contents suited to the user's preference. Efficiency of previous IEC studies was generally investigated from the view point of optimization. However, few previous studies paid attention to their efficiency as a reflection of individual preferences. As an application of IEC, we already proposed a method that creates sign sounds using paired comparison‐based interactive differential evolution (IDE). This study investigates the efficiency of the IDE for reflecting individual difference on the created sound through two experiments. In Experiment 1, the subjects searched better warning sounds with the IDE. The result of Experiment 1 showed gradual convergence of DE's vectors. In Experiment 2, the subjects evaluated four sign sounds created in Experiment 1. Two of them were created by the subject, and the other two were created by another subject. The result of Experiment 2 showed significant increase in the subjective fitness value for sounds created by the subjects themselves. Furthermore, significant difference between sounds by one subject and another was observed in the final generation. These results suggest that IDE is effective in creating warning sounds suited to each user reflecting individual difference. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Temporal resolution of the skin impedance measurement in frequency-domain method

The temporal-resolution of the frequency-domain method for the identification of the impedance locus depends on the basis frequency used in the current waveform construction, i.e., the higher basis frequency provides the better temporal resolution. The impedance locus can be characterized by the impedance parameters Z0, beta, and taum. The frequency distribution of limited number of data in the impedance locus would affect the accuracy of the estimated impedance parameters. Therefore, we investigated the relationship between the estimation accuracy of the impedance parameters and the frequency coverage of the impedance locus in relatively low to high impedance conditions (dc impedance Z0= 51 k ohms - 45 M ohms). As the basis frequency, 100 Hz was enough for the usual impedance with Z0 less than 203 k ohms. On the other hand, 10 Hz and 1 Hz were required for the medium-level (Z0 = 517 k ohms), and high-level (Z0 = 45 M ohms) impedance, respectively. The required basis frequency, accordingly the temporal resolution, depended much on the central relaxation time taum which affects the frequency distribution on the impedance locus. The results of this study are expected to serve as the reference of the frequency selection in the frequency-domain analysis of the skin impedance.     

Polarized optical reflection study on single crystalline β-FeSi<Subscript>2</Subscript>

Polarized optical reflectance of single crystalline β-FeSi₂ has been investigated up to 3.1 eV for the light polarization of E//a, E//b and E//c. We observed the clear anisotropy in the spectrums of reflectance, refractive index n, extinction coefficient k and dielectric function ε, depending on the light polarizations. From the comparison with the experiments and the theoretical calculation, we found that features of those experimental spectrums agrees well with the theoretical ones calculated by the full potential linear augmented plane wave method based on the density functional theory and the dipole approximation. The anisotropy of n was found to be 10–20% between 1 eV and 3.1 eV, while it was small (<～ 5%) below 1 eV.     

Glass Substrates for OLED Lighting with High Out-coupling Efficiency

Glass substrates which realize high out-coupling efficiency OLEDs （organic light emitting diodes） were developed. A scattering layer whose matrix was made of high refractive index glass was formed on a glass substrate, and pores in the glass matrix work as scattering centers. The out-coupling efficiency of an OLED using this substrate is 1.8 times higher compared with an OLED using an untreated glass substrate. Furthermore angular dependency of the color and color variation between panels can be successfully suppressed.     

Urinary bisphenol A concentrations and their implications for human exposure in several Asian countries

Bisphenol A (BPA) is an industrial chemical used in the manufacture of polycarbonate plastics and epoxy resins. Due to the potential of this compound to disrupt normal endocrinal functions, concerns over human exposure to BPA have been raised. Although several studies have reported human exposure to BPA in Western nations, little is known about exposure in Asian countries. In this study, we determined total urinary BPA concentrations (free plus conjugated) in 296 urine samples (male/female: 153/143) collected from the general population in seven Asian countries, China, India, Japan, Korea, Kuwait, Malaysia, and Vietnam, using high-performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS). On the basis of urinary BPA concentrations, we estimated the total daily intake. The results indicated that BPA was detected in 94.3% of the samples analyzed, at concentrations ranging from <0.1 to 30.1 ng/mL. The geometric mean concentration of BPA for the entire sample set from seven countries was 1.20 ng/mL. The highest concentration of BPA was found in samples from Kuwait (median: 3.05 ng/mL, 2.45 μg/g creatinine), followed by Korea (2.17 ng/mL, 2.40 μg/g), India (1.71 ng/mL, 2.09 μg/g), Vietnam (1.18 ng/mL, 1.15 μg/g), China (1.10 ng/mL, 1.38 μg/g), Malaysia (1.06 ng/mL, 2.31 μg/g), and Japan (0.95 ng/mL, 0.58 μg/g). Among the five age groups studied (≤ 19, 20-29, 30-39, 40-49, and ≥ 50 years), the highest median concentration of BPA was found in urine samples from the age group of ≤ 19 years. There was no significant difference in BPA concentrations between genders (male and female) or domicile of residence (rural and urban). The estimated median daily intakes of BPA for the populations in Kuwait, Korea, India, China, Vietnam, Malaysia, and Japan were 5.19, 3.69, 2.90, 2.13, 2.01, 1.80, and 1.61 μg/day, respectively. The estimated daily intake of BPA in the seven Asian countries was significantly lower than the tolerable daily intake recommended by the U.S. Environmental Protection Agency. This is the first study to document the occurrence of and human exposure to BPA in several Asian countries.     

Silica and titanium dioxide nanoparticles cause pregnancy complications in mice

The increasing use of nanomaterials has raised concerns about their potential risks to human health. Recent studies have shown that nanoparticles can cross the placenta barrier in pregnant mice and cause neurotoxicity in their offspring, but a more detailed understanding of the effects of nanoparticles on pregnant animals remains elusive. Here, we show that silica and titanium dioxide nanoparticles with diameters of 70 nm and 35 nm, respectively, can cause pregnancy complications when injected intravenously into pregnant mice. The silica and titanium dioxide nanoparticles were found in the placenta, fetal liver and fetal brain. Mice treated with these nanoparticles had smaller uteri and smaller fetuses than untreated controls. Fullerene molecules and larger (300 and 1,000 nm) silica particles did not induce these complications. These detrimental effects are linked to structural and functional abnormalities in the placenta on the maternal side, and are abolished when the surfaces of the silica nanoparticles are modified with carboxyl and amine groups.     

Air Purification Capability of Charcoal and Its Evaluation

Charcoal has received much attention recently because of the various kinds of effective functions it can be put to. Especially, its deodorizing capability indoors has been well recognized. However, an evaluation method for this capability has not been established. It is necessary to devise a suitable method and introduce this capability to the general public using an index value. They can then understand the capability easily by the value and use it positively. In this study, an evaluation method is proposed, wherein the deodorizing capability of charcoal is evaluated in an experimental chamber using a tin oxide gas sensor, which outputs a signal according to the concentration of an air‐polluting chemical. The sensor output increases as the concentration of the chemical increases. The index value (P_a) indicating the capability can be represented using the sensor output characteristic to the chemical, using the peak value (h) and the half‐value width (t_w); P_a = h/t_w × 100. The peak value here means the voltage from offset level to the peak value of the output. Four kinds of charcoals were examined. Especially, charcoal from Japanese cedar and oak were investigated. The results show that both samples give almost same value (P_a = ∼10). Cedar charcoal is cheaper and the heat energy required is also lower than for oak charcoal. This is good for cedar charcoal. It is considered that by installing charcoal in an indoor environment the air quality can be improved and people can have a safe and comfortable life. Charcoal has therefore the capability to remediate indoor air pollution. © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

A link selection method for web‐browser using eye‐gaze input

Methods for browsing Web pages using eye‐gaze input have been proposed for severely physically handicapped people who cannot handle a computer mouse to utilize convenient services on the Internet. There are two important functions for Web‐browsers, namely scroll and link selection. Since it is difficult to introduce existing link selection methods using eye‐gaze input for home usage because of high costs or complexity, we propose in this paper a novel link selection method using eye‐gaze input. The proposed method analyzes the HTML source in a Web page and makes a group of links by the content of each. In evaluation experiments, we compare the proposed method with a comparative method using eye‐gaze input with respect to the average response time in selecting the links. The results of the experiments show that the average response is nearly twice as fast as that of the compared method. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.