Sanghyun Kwon

A Research on Curved Display Comparing to Flat Display Regarding Posture, Tilt Angle, Focusing Area and Satisfaction

Objective: This study is conducted on the differences between flat and curved displays with respect to location of focused points, posture and satisfaction as well as preferred tilt angles. Background: In order to avoid physical and eye fatigue caused by misplayed sitting posture, many studies have asserted that the display requires appropriate location, size and tilt angle as well as curvature. However, most studies have focused on the work environment and the results are varied in the extent. Method: Eye height data in sitting posture were collected from 30 participants. Participants selected the most comfortable viewing angle within the range from 0° to 12° while watching videos for both curved and flat display. Then, physical and eye fatigue and overall satisfaction were subjectively evaluated. Lateral diagram describing viewing display condition was set and used to develop linear models for expecting the preferred tilt angle. Results: Due to sitting in the natural viewing posture rather than upright, the eye height is lowered to about 4.6 centimeters, on average, for both displays showing no significant differences. In contrast, preferred angles for the two displays are significantly different and this can be interpreted that curvature vary the points focused. Two linear models as functions of sitting eye height are developed to expect preferred tilt angle for each display. Based on the result of overall satisfaction evaluation, curved display is statistically better than flat display. Conclusion: The results show that flat and curved displays are significantly different expect for the viewing posture. However, reasons for preferring curved display are not accurately factorized and the linear models are limited in the experiment condition such as size of display, distance between display and viewer and other physical environmental factors. Further studies on curved displays under more various conditions are required. Application: This study can contribute to use of the curved display in various way.

Research Issues in Smart Vehicles and Elderly Drivers: A Literature Review

This article reviewed both studies on general smart car technologies and human–computer interaction (HCI)/human–vehicle interaction studies that were published in journals and conferences so that the current status of research can be identified and future research directions can be suggested. Furthermore, previous studies on elderly drivers were reviewed, as these drivers could be the most vulnerable social group in terms of new technology acceptance. A total of 257 articles for HCI research and 45 articles for elderly drivers were selected and reviewed from 11,267 collected articles (2010–2014). According to the results, most articles were mainly related to safety and adaptive features (e.g., driver’s state recognition, vehicle surrounding monitoring, driver action-suggestion), and infotainment research in terms of HCI (e.g., information technology devices–vehicle interaction, vehicle–vehicle interaction) was relatively insufficient despite its high research demand. According to the results of the literature review and technological trends analysis based on previous technical road maps, from HCI/human factors engineering (HFE) perspectives, research related to “Assistance systems,” “Physiological & mental state recognition,” “Position sensor technology,” “Behavior recognition,” and “Infotainment” was suggested to HCI/HFE researchers for further research. In particular, HCI/HFE researchers need to focus on research on acceptable levels of automation, observing new driving behaviors, investigation of driver characteristics to develop personalized services, and new technology acceptance to develop and improve smart cars in the future.

Effects of Grip Curvature and Size of Hand on Comfort for the Unimanual Operation of Handheld Touchscreen Device

This study aims to investigate the effect of size of a hand and curvature of handheld touchscreen devices on comfort when unimanually using the devices. By rated subjectively and recording EMG, comfort was measured for the use of three mock-ups of the device with different curvatures; one had flat surface and the others had curvatures of 400R and 100R for each. During the experiment, tapping, typing and dragging tasks were performed and the participants evaluated comfort subjectively and objectively. A difference among curvatures was analyzed as well as a difference among participant groups classified by size of their preferred hand. The results indicated that curvature of the handheld touchscreen devices affected neither muscle activities nor subjective comfort level. Moreover, size of hand was found to affect comfort objectively measured, but not the one subjectively rated. Overall, this study suggests that comfort measured subjectively does not consistent with comfort measured by objective data. Also, users’ hand size may be more critical factor than curvature of handheld touchscreen determining comfort of touch screen use.

Generating a research keyword structure on human haptic interaction using a social network analysis tool

The field of haptic interaction is inherently multidisciplinary and adopts knowledge from many areas, including robotics, experimental psychology, biology, computer science, systems and control, and others. It is an important first step in research reviewing overall areas of hap-tic related researches, as well as reviewing the specific area of focus. For this purpose, it is important to ensure objective research direction based on the clear and enlightening analysis of the research trends in this field. This study aims to identify the relationship among overall areas of haptic related researches using a network analysis technique. We collected keywords of haptic related researches from several journals and used those as an input for conducting network analysis. Then, we also classified the areas of haptic researches by analyzing the relationship among keywords. From the network analysis, we found that haptic related researches could be classified into two areas; (1) Technology perspectives related to the application of haptic technology and (2) User perspectives related to the perception of haptic sensation. The keyword structure generated from this study is expected to provide basic knowledge on the trend and current status of researches in human haptic inter-action.

Analysis of stature prediction from foot anthropometry: a South Korean case study

The investigation of footprints or dismembered foot dimensions from the scene of a crime or disaster plays a crucial role in the effort to determine some characteristics of the suspects or victims. Previous studies have shown the importance of foot dimensions for that purpose. However, the foot length and foot breadth were frequently studied; the present research investigated the relationship between stature and diverse foot dimensions such as of the heel, metatarsal edge, instep, metatarsal, and lateral malleolus – in addition to the foot length and foot breadth. The feet of 461 subjects (175 male & 286 Female) were scanned and measured. The mean age of the male participants was 41.6 (from 20 to 69) and 38.4 for female participants (from 20 to 68). A t-test was used to compare the gender difference in each dimension. Pearson’s correlation coefficients were computed to identify correlations among various part measurements and heights. Regression equations were derived using single or multiple variables. Foot length showed the highest relationship in males (R = 0.753) and females (R = 0.433). For males and females, prediction accuracy was highest in the linear regression equation using foot length alone (R2 = 0.567 for males, R2 = 0.188 for females; SEE ± 4.332 cm for males, ±4.825 cm for females). In addition to foot length, length-related variables such as the distance from the heel to both ends of the metatarsal were also reliable predictors. These research results are expected to be useful information for forensic medicine, and for medical appliance and sports manufacturers.