The illuminance and color temperature of a light source affect the perceived atmosphere of interior lighting. However, few studies have investigated the environmental lighting preferences of people in developing countries, such as those in Southeast Asia. In particular, the evaluation characteristics of people who live in such areas have not been clarified. Therefore, we conducted an experiment on interior lighting to determine the difference in the evaluation characteristics of illuminance and color temperature between Japanese and Thai people. As a result, we found a significant difference in their preferred brightness for interior lighting. Thai people evaluated low illuminance interior lighting as being brighter than Japanese people.
A method for predicting statistical deterioration using visual inspection data for tunnel luminaires has been developed. The method uses the mixed Markov deterioration hazard model to first calculate the expected deterioration path and expected lifespan of luminaires on the basis of the statistical analysis of deterioration factors and then to estimate the deterioration path on the basis of the heterogeneity of the deterioration process of each luminaire or group of luminaires. The hierarchical Bayesian estimation method is suggested as a concrete model estimation method. To verify the effectiveness of the proposed method, empirical analysis was carried out using the visual inspection data for 10,584 luminaires located in 11 tunnels. The deterioration process depended significantly on the tunnel grade and the distance from the tunnel entrance. The expected lifespan of the luminaires was about 13.6 years and varied by about 4.3 years in accordance with the above factors. The expected lifespan of the luminaires varied from 6.9 to 17.5 years in accordance with the heterogeneity of each tunnel.
Vertically aligned ZnO nanowires were directly grown on a Mg-doped GaN substrate by nanoparticle-assisted pulsed laser deposition (NAPLD) without a catalyst. The photo luminescence of the ZnO nanowires at room temperature shows visible emission, which may be attributed to the point defects in the ZnO. A ZnO nanowire/GaN heterojunction LED was fabricated by preparing an insulating film of SOG (spin-on-glass) and electrodes. Electroluminescence at a wavelength of 500 to 900 nm was observed at room temperature under forward bias.
Right after the Great East Japan Earthquake on March 11,2011, we examined the lighting in Kamaishi City , Iwate Prefecture that facilitates evacuation to higher ground away from a tsunami at night. From the investigation of the escape routes for evacuees in the center of the city and experiments at the entrance of evacuation destinations, it was found that a series of lights placed along the evacuation paths in the direction toward higher ground could guide evacuees effectively to the safe areas. Then, the evacuation performances were investigated in this lighting environment. Based on this research, it was decided that lighting of the evacuation area entrance should be improved preferentially, and lighting of the city streets and intersections should be installed continuously.