Sangwoo Bahn

Acceptance of Assistive Technology by Special Education Teachers: A Structural Equation Model Approach

To investigate the acceptance of assistive technology (AT) by special education teachers, the present study developed and tested hypothesized relationships among key determinants of AT acceptance such as the facilitating condition, perceived ease of use, computer self-efficacy, result demonstrability, perceived usefulness, and behavioral intention. Results from analysis of data collected from a number of special education teachers in schools for the visually and/or auditory impaired confirmed the effects hypothesized in our conceptual model of AT acceptance. In particular, perceived usefulness was a dominant factor affecting AT usage. Facilitating condition was strongly related to perceived ease of use, whereas perceived ease of use had a significant effect on computer self-efficacy. This study also found the importance of result demonstrability factor, which had significant effects on both computer self-efficacy and perceived usefulness. This study expanded and enriched a traditional technology acceptance model by further investigating determinants associated with the acceptance of AT by special education teachers for the blind and/or the deaf. In addition, the results of the present study should provide some insights into the understanding of AT acceptance and the decisions of AT utilization, as well as its distribution and training.

Effects of Luminosity Contrast and Stimulus Duration on User Performance and Preference in a P300-Based Brain–Computer Interface

Brain–computer interfaces (BCI) have potential to provide a new channel of communication and control for people with severe motor disabilities. Although many empirical studies exist, few have specifically evaluated the impact of contributing factors on user performance and perception in BCI applications, especially for users with motor disabilities. This article reports the effects of luminosity contrast and stimulus duration on user performance and usage preference in a P300-based BCI application, P300 Speller. Ten participants with neuromuscular disabilities (amyotrophic lateral sclerosis and cerebral palsy) and 10 able-bodied participants were asked to spell six 10-character phrases in the P300 Speller. The overall accuracy was 76.5% for the able-bodied participants and 26.8% for participants with motor disabilities. The results showed that luminosity contrast and stimulus duration have significant effects on user performance. In addition, participants preferred high luminosity contrast with middle or short stimulus duration. However, these effects on user performance and preference varied for participants with and without motor disabilities. The results also indicated that although most participants with motor disabilities can establish BCI control, BCI illiteracy does exist. These results of the study should provide insights into the future research of the BCI systems, especially the real-world applicability of the BCI applications as a nonmuscular communication and control system for people with severe motor disabilities.

Severe motor disability affects functional cortical integration in the context of brain–computer interface (BCI) use

The purpose of this study was to investigate cortical interaction between brain regions in people with and without severe motor disability during brain–computer interface (BCI) operation through coherence analysis. Eighteen subjects, including six patients with cerebral palsy (CP) and three patients with amyotrophic lateral sclerosis (ALS), participated. The results showed (1) the existence of BCI performance difference caused by severe motor disability; (2) different coherence patterns between participants with and without severe motor disability during BCI operation and (3) effects of motor disability on cortical connections varying in the brain regions for the different frequency bands, indicating reduced cortical differentiation and specialisation. Participants with severe neuromuscular impairments, as compared with the able-bodied group, recruited more cortical regions to compensate for the difficulties caused by their motor disability, reflecting a less efficient operating strategy for the BCI task. This study demonstrated that coherence analysis can be applied to examine the ways cortical networks cooperate with each other during BCI tasks. Practitioner Summary: Few studies have investigated the electrophysiological underpinnings of differences in BCI performance. This study contributes by assessing neuronal synchrony among brain regions. Our findings revealed that severe motor disability causes more cortical areas to be recruited to perform the BCI task, indicating reduced cortical differentiation and specialisation.

Does Touch Matter?: The Effects of Haptic Visualization on Human Performance, Behavior and Perception

Chang S. Nam1, Paul Richard2, Takehiko Yamaguchi3, and Sangwoo Bahn4 1Edward P. Fitts Department of Industrial and Systems Engineering, North Carolina State University, Raleigh, North Carolina, USA 2Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS), Université d’Angers, Angers, France 3Department of Applied Electronics, Tokyo University of Science, Tokyo, Japan 4Department of Industrial and Management Engineering, Myongji University, Yongin, Korea

Performance Analysis of Text Entry with Preferred One Hand using Smart Phone Touch-keyboard

Is performance in smartphone text entry better when using the preferred hand rather than the non-preferred hand? Among right-handed people, is the performance of users who prefer using their left hand in smartphone text entry worse than that of users who prefer using their right hand? The present study addresses these questions. Thirty young male undergraduate students were instructed to type a text message template using a thumb-based QWERTY smartphone with both hands, with only their right hand, and with only their left hand. The completion time and occurrence of errors were measured. All participants were right handed. However, when only one hand is available half of them preferred to use their right hand if they had to enter a text on the smartphone, whereas the other half preferred to use their left hand. In entering a text with only one hand, about 90% of the 15 righthand-preferred participants, and about 70% of the 15 lefthand-preferred participants performed better using their preferred hand than using their nonpreferred hand. However, the performance of the participants who performed better using their left hand was not worse than those who performed better using their right hand in smartphone text entry.

A statistical model of relationship between affective responses and product design attributes for capturing user needs

Customers satisfaction is a critical factor to a products success and identifying key affective response factors which customers mainly perceive is critical to satisfy customers. This study aims to identify the key affective response factor of satisfaction for passenger car interior material using statistical approach. Related variables of satisfaction consisting of 10 affective response variables associated with look-and-feel and touch feel of a surface material was systematically identified through literature survey, customer reviews, and expert opinions. Thirty participants evaluated 41 different crash pad samples using a questionnaire survey with 9-point semantic differential scale and 100-point scale. Based on the survey results, softness was identified as the key affective response factor of satisfaction for car crash pad. Then the relationship between softness and related engineering variables was identified. It is expected that the results could suggest the optimal combination and provide specific design guidelines quantitatively.

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.

Development of a job rotation scheduling algorithm for minimizing accumulated work load per body parts

BACKGROUND For the successful implementation of job rotation, jobs should be scheduled systematically so that physical workload is evenly distributed with the use of various body parts. However, while the potential benefits are widely recognized by research and industry, there is still a need for a more effective and efficient algorithm that considers multiple work-related factors in job rotation scheduling. OBJECTIVE This study suggests a type of job rotation algorithm that aims to minimize musculoskeletal disorders with the approach of decreasing the overall workload. METHODS Multiple work characteristics are evaluated as inputs to the proposed algorithm. Important factors, such as physical workload on specific body parts, working height, involvement of heavy lifting, and worker characteristics such as physical disorders, are included in the algorithm. For evaluation of the overall workload in a given workplace, an objective function was defined to aggregate the scores from the individual factors. A case study, where the algorithm was applied at a workplace, is presented with an examination on its applicability and effectiveness. RESULTS With the application of the suggested algorithm in case study, the value of the final objective function, which is the weighted sum of the workload in various body parts, decreased by 71.7% when compared to a typical sequential assignment and by 84.9% when compared to a single job assignment, which is doing one job all day. CONCLUSIONS An algorithm was developed using the data from the ergonomic evaluation tool used in the plant and from the known factors related to workload. The algorithm was developed so that it can be efficiently applied with a small amount of required inputs, while covering a wide range of work-related factors. A case study showed that the algorithm was beneficial in determining a job rotation schedule aimed at minimizing workload across body parts.

Influence of haptic feedback on a pointing task in a haptically enhanced 3D virtual environment

To gain a better view of the value of haptic feedback, human performance and preference in a pointing style task in a three-dimensional virtual environment was explored. Vibration and haptic attractive force were selected as two simple cases of feedback, each with two levels. These types of feedback were compared to a no-feedback condition to better understand how human performance changes under these conditions. The study included 8 undergraduate students. A Novint Falcon haptic controller was used in a simulated three-dimensional virtual environment. Analysis was conducted on how each type of feedback effects the movement time (MT) of users. The results showed that vibration was perceived negatively and had a slight negative impact on performance. The haptic attractive force significantly improved performance and was strongly preferred by subjects.

Assessing the effectiveness of vibrotactile feedback on a 2D navigation task

The effect of vibrotactile parameters were investigated on a 2D navigation task. Participants performed a simple navigation task reproducing directional information presented by a series of vibrotactile stimuli consisting of different levels of amplitude and frequency. Task completion time and degree of annoyance were measured. The results demonstrated that both frequency and amplitude had a significant effect on the responses. In addition, interaction effects between the two parameters were found on the responses. It was concluded that user performance and comfort are significantly affected by frequency and amplitude. The results give some insight into designing navigating information presented by vibrotactile display for visually impaired people. More studies with people with visual impairment and manipulation of other vibrotactile parameters are recommended to be applicable to the potential research.