Dynamic lighting system for the learning environment: performance of elementary students.

This study aims to investigate the effects of lighting color temperatures on elementary students' performance, and thereby propose a dynamic lighting system for a smart learning environment. Three empirical studies were conducted: First, physiological responses were measured as a potential mediator of performance. Second, cognitive and behavioral responses were observed during academic and recess activities. Lastly, the experiment was carried out in a real-life setting with prolonged exposure. With a comprehensive analysis of the three studies, three lighting presets-3500 K, 5000 K, and 6500 K-are suggested for easy, standard, and intensive activity, respectively. The study is expected to act as a good stepping stone for developing dynamic lighting systems to support students' performance in learning environments.

Assessment of white for displays under dark- and chromatic-adapted conditions.

This study aims to investigate the white perception of mobile display devices under dark-adapted and chromatic-adapted conditions. The white perception was modeled with error ellipses and bivariate Gaussian distributions. The dark-adapted white encompassed a rather large area centered around 7300 K, slightly above the Planckian locus. The chromatic-adapted whites were highly dependent on the ambient illuminant, and were not parallel to the Planckian locus. Combined, the white region encompassing 6179 to 7479 K in correlated color temperature and -0.0038 to 0.0144 in Duv was suggested. The results of this study are expected to be the basis for enhanced white appearance on mobile display devices.

Adaptive display luminance for viewing smartphones under low illuminance.

The study investigates the optimal display luminance for viewing smartphones in conditions of low illuminance. This proposes a model of adaptive display in that display luminance changes gradually with the passage of watching time. It starts at a fairly low display luminance of 10 cd/m2, and after 10 seconds, the luminance increases slowly until it reaches 40 cd/m2 for 20 seconds and maintains the luminance. For the development of the model, an experiment was conducted to identify the optimal luminance for initial viewing and that for continuous viewing, as well as the change speed of display luminance. In order to validate the model, users' subjective judgments and activation of alpha rhythm were observed, and the result confirmed the superiority of the adaptive display luminance compared to the current display luminance in terms of physiological comfort and psychological satisfaction. It is expected that this study contributes to the pleasing use of displays at night under low illuminance by applying to diverse types of display devices.

Brightness and hue judgment of dyed hair color.

This study aims to investigate human hair color perception through two empirical studies in the context of colored hair. The preliminary study was intended to establish a numerical representation of perceptually meaningful brightness levels. It identified that the brightness level was proportional to the power of 0.766 of L*. In the visual assessment, participants (N = 47) categorized 246 hair color samples into eight color hue groups aligned with the Munsell system. Hue judgment was conducted by visually comparing dyed hair tresses with natural black hair. Based on the L*, a*, and b* values of hair tresses and visual assessments thereof, we observed the ranges of hue categories for hair color alongside the brightness levels. Additionally, the differences between the Munsell hue names and the assessment results were compared. Predominantly influenced by the dark brown hair color, the neutral orientation was shifted to the first quadrant of the a*-b* plane. The study contributes to an understanding of human hair color perception and provides insights into color categorization and labeling, especially when the context is confined.

Advancing Breathability of Respiratory Nanofilter by Optimizing Pore Structure and Alignment in Nanofiber Networks.

Respiratory masks are the primary and most effective means of protecting individuals from airborne hazards such as droplets and particulate matter during public engagements. However, conventional electrostatically charged melt-blown microfiber masks typically require thick and dense membranes to achieve high filtration efficiency, which in turn cause a significant pressure drop and reduce breathability. In this study, we have developed a multielectrospinning system to address this issue by manipulating the pore structure of nanofiber networks, including the use of uniaxially aligned nanofibers created via an electric-field-guided electrospinning apparatus. In contrast to the common randomly collected microfiber membranes, partially aligned dual-nanofiber membranes, which are fabricated via electrospinning of a random 150 nm nanofiber base layer and a uniaxially aligned 450 nm nanofiber spacer layer on a roll-to-roll collector, offer an efficient way to modulate nanofiber membrane pore structures. Notably, the dual-nanofiber configuration with submicron pore structure exhibits increased fiber density and decreased volume density, resulting in an enhanced filtration efficiency of over 97% and a 50% reduction in pressure drop. This leads to the highest quality factor of 0.0781. Moreover, the submicron pore structure within the nanofiber networks introduces an additional sieving filtration mechanism, ensuring superior filtration efficiency under highly humid conditions and even after washing with a 70% ethanol solution. The nanofiber mask provides a sustainable solution for safeguarding the human respiratory system, as it effectively filters and inactivates human coronaviruses while utilizing 130 times fewer polymeric materials than melt-blown filters. This reusability of our filters and their minimum usage of polymeric materials would significantly reduce plastic waste for a sustainable global society.

Method and analysis of color changes of facial skin after applying skin makeup.

This study investigated facial skin color differences before and after makeup. Toward this goal, a photo gauge, devised with a pair of color checkers as a reference, collected face images. In addition, color calibration and a deep-learning method extracted the color values of representative areas of facial skin. The photo gauge photographed 516 Chinese females before and after applying makeup. Then, the collected images were calibrated by referencing skin color patches, and the lower cheek regions' pixel colors were extracted using open-source computer vision libraries. Following the visible color spectrum of humans, the color values were computed in L*, a*, and b* of CIE1976L*a*b*. The results showed that the facial colors of the Chinese females changed to become brighter, less reddish, and less yellowish after applying the makeup, resulting in a paler skin tone. During the experiment, subjects were given five varieties of liquid foundation to choose one sample that best fits their skin. However, we failed to find any noticeable relationship between the individual's facial skin color characteristics and the liquid foundation selected. In addition, 55 subjects were identified according to their makeup use frequency and skill, but their color changes did not differ from the other subjects. This study provided quantitative evidence of makeup trends in the Shanghai region in China, and the method proposes a novel approach toward remote skin color research.

Awakening effects of blue-enriched morning light exposure on university students' physiological and subjective responses.

We investigated physiological and subjective responses to morning light exposure of commercially available LED lighting with different correlated colour temperatures to predict how LED-based smart lighting employed in future learning environments will impact students. The classical markers of the circadian system (melatonin and cortisol), as well as the subjective perception of sleepiness, mood, and visual comfort, were compared. Fifteen university students underwent an hour of morning light exposure to both warm (3,500 K) and blue-enriched (6,500 K) white lights at recommended illuminance levels for classrooms and lecture halls (500 lux). The decline of melatonin levels was significantly greater after the exposure to blue-enriched white light. Exposure to blue-enriched white light significantly improved subjective perception of alertness, mood, and visual comfort. With regard to cortisol, we did not find a significant difference in the cortisol decrement between the two light conditions. Our findings suggest that the sensitivity of physiological and subjective responses to white LED light is blue-shifted. These findings, extending the already known effects of short-wavelength light on human physiology, reveal interesting practical implications. Blue-enriched LED light seems to be a simple yet effective potential countermeasure for morning drowsiness and dozing off in class, particularly in schools with insufficient daylight.

Context-based presets for lighting setup in residential space.

This study aims to derive context-based lighting setup presets in residential space by exploring the multilateral relationships among household activities, affects, and lighting setups. Three procedures were involved: First, sixty affective words were evaluated through which seven affect factors were extracted to facilitate the evaluation of colored illumination in the subsequent experiment. Second, in the user study, seven affect factors and thirty household activities were used to evaluate 147 lighting setups extracted from combinations of twelve hues, six illuminance levels, and three purity levels. As a result, twenty lighting setup presets were derived that were not only activity-based, but affect-based as well. Lastly, the twenty presets were prototyped as a set of testbed to further explore potentials and limitations. This study demonstrates that intuitive, context-based presets can help users explore the effects of colored illumination in creating a diverse range of user experiences.