Effect of sitting or standing on touch screen performance and touch characteristics

Interface Design of Head-Worn Display Application on Condition Monitoring in Aviation

Head-worn displays (HWDs) as timely condition monitoring are increasingly used in aviation. However, interface design characteristics that mainly affect HWD use have not been fully investigated. The aim of this study was to examine the effects of several important interface design characteristics (i.e., the distance between calibration lines and the layouts of vertical and horizontal scale belts) on task performance and user preference between different conditions of display, i.e., HWD or head-up display (HUD). Thirty participants joined an experiment in which they performed flight tasks. In the experiment, the calibration lines' distance was set to three different levels (7, 9 and 11 mrad), and the scale belt layouts included horizontal and vertical scale belt layouts. The scale belts were set as follows: the original vertical scale belt width was set as L, and the horizontal scale belt height as H. The three layouts of the vertical calibration scale belt used were 3/4H, H and 3H/2. Three layouts of horizontal calibration scale belts were selected as 3L/4, L and 3L/2. The results indicated that participants did better with the HWD compared to the HUD. Both layouts of vertical and horizontal scale belts yielded significant effects on the users' task performance and preference. Users showed the best task performance while the vertical calibration scale belts were set as H and horizontal calibration scale belts were set as L, and users generally preferred interface design characteristics that could yield an optimal performance. These findings could facilitate the optimal design of usable head-worn-display technology.

Effect of icon size, icon position and sex on clicking motion when operating smartphones with single hand

Nowadays, increasingly more situations exist where smartphones are operated with one hand, requiring an in-depth understanding of human-computer interaction in single-hand scenarios. 104 volunteers (57 men, 47 women) participated in this study. We aimed to explore thumb movements with the right and left hand on smartphone touchscreens at different icon sizes (50, 80, 110 and 140 rpx) in different operation areas (a 4*7 icon matrix). The results partially conformed to Fitts' Law. The movement time (MT) significantly increased as the icon size decreased, but this effect was not found over 110 rpx. The MT increased with distance in the vertical direction, but icons with the same horizontal distance had different MTs, indicating that one-handed operation restricted the click on the same side. Additionally, subjects rated 140 rpx better than other sizes, and men clicked faster than women. Suggestions regarding one-handed interface design for different hands of different sexes are provided. Practitioner summary: This study investigated how icon size, position and sex influenced one-thumb click usability on touch-screen mobile phones with different hands of different sexes. The results indicate single-hand operation partially conformed to Fitts' Law. We suggested the most economical and comfortable size and the fast operation area in one-handed interface design.Abbreviations: MT: movement time; ID: index of difficulty; RPX: responsive pixel; NASA-TLX: task load index of National Aeronautics and Space Administration; ANOVA: analysis of variance.

The Effects of Standing Working Posture on Operation Force and Upper Limb Muscle Activation When Using Different Pointing Devices

This study investigated how sitting and standing working postures affected operation force, upper limb muscle activation, and task performance using different pointing devices. Fifteen male participants completed cursor aiming and dragging tasks using a conventional mouse, a vertical mouse, and a trackball at sitting and standing workstations. A custom-made force plate was used to measure operation forces applied to the pointing devices. Surface electromyography (EMG) was used to capture the activation of the biceps brachii, triceps brachii, deltoid, and trapezius. Task performance was measured by task success rates, and subjective ratings were obtained for the force required for operation, smoothness of operation, accuracy, and local fatigue in the upper limb. We quantified the following significant outcomes: (1) greater operation forces were found when standing; (2) standing reduced EMG amplitudes of the triceps and trapezius muscles for all tasks; (3) during the aiming task, the vertical mouse had greater operation forces; (4) during the dragging task, both the vertical mouse and trackball had greater operation forces; and (5) task success rates differed for pointing devices only when sitting. This study revealed the distinct biomechanical properties of standing working posture and suggested limited beneficial effects of alternative pointing devices in terms of task performance and subjective ratings.

Typing with mobile devices: A comparison of upper limb and shoulder muscle activities, typing performance and perceived workload under varied body postures, typing styles and device types

This study aimed to examine the effects of body posture, typing style and device type on upper limb and shoulder muscle activities, typing performance and perceived workload while typing with mobile devices. Participants were asked to type with two mobile devices (i.e., a tablet and a smartphone) under three postures and in two typing styles. Muscle activity was recorded for four upper limb and shoulder muscles on both sides with surface electromyography. Results showed that body posture and typing style yielded significant effects on tying performance, perceived workload, and muscle activities in the forearm, upper arm and shoulder. Typing with a tablet was more accurate and had greater muscle activities in the upper arm and forearm on both sides than typing with a smartphone. The findings may be useful in developing evidence-based guidelines for the wise use of mobile devices and for the prevention of risks for musculoskeletal disorders.

Study on Smart Home Interface Design Characteristics Considering the Influence of Age Difference: Focusing on Sliders

Smart homes represent an effective approach to improve one's quality of life. Developing user interfaces that are both comfortable and understandable can assist users, particularly the elderly, embrace smart home technologies. It's critical to concentrate on the characteristics of smart home interface design and their impact on people of various ages. Since sliders are one of the most common components utilized in the smart home user interface, this article aimed to investigate the effects of slider design characteristics (e.g., button size, track color, and sliding orientation) on user performance and preference. Thirty-four participants were recruited for the experiment (16 for the young group, aged between 18 and 44 years; 18 for the middle-aged and elderly group, aged between 45 years and above). Our results revealed that both groups had shorter task completion time, less fixation time, and saccades on horizontal sliding orientation and larger buttons, which means better user performance. For the older group, the slider with color gradient track led to better user performance, while the track color only had less effect on the performance of the younger group. In terms of user preference, the results and performance of the older group were basically consistent, while the younger group had no significant difference in sliding orientation and track color.

The Effects of Smart Home Interface Touch Button Design Features on Performance among Young and Senior Users

Touch technology-based smart homes have become increasingly prevalent, as they can help people with independent daily life, especially for the elderly. The aim of this study was to investigate the effects of button features (i.e., button size, graphics/text ratio, and icon style) in smart home interfaces on user performance across two age groups. Participants in the young group (n = 15) and senior group (n = 15) completed a clicking task. Button size ranged from 10 mm to 25 mm with 5 mm increments. The three levels of graphics/text ratio were 3:1, 1:1, and 1:3, while icon style was either flat or skeuomorphic. Results showed that button size and graphics/text ratio had significant effects on user performance in both groups, whereas icon style only had an effect in the senior group. It was observed that the elderly were fond of buttons with a larger size of 20 mm with larger texts and skeuomorphic icons, whereas the young preferred a button size of 15 mm with equal-sized graphics and text. These results may help to improve the accessibility and usability of smart home interface design.

Interaction with touchscreen smartphones in patients with essential tremor and healthy individuals

INTRODUCTION

Smartphone use in biomedical research is becoming more prevalent in different clinical settings. We performed a pilot study to obtain information on smartphone use by patients with essential tremor (ET) and healthy controls, with a view to determining whether performance of touchscreen tasks is different between these groups and describing touchscreen interaction factors.

METHOD

A total of 31 patients with ET and 40 sex- and age-matched healthy controls completed a descriptive questionnaire about the use of smartphones. Participants subsequently interacted with an under-development Android application, and performed 4 tests evaluating typical touchscreen interaction gestures; each test was performed 5 times.

RESULT

The type of smartphone use and touchscreen interaction were not significantly different between patients and controls. Age and frequency of smartphone use are key factors in touchscreen interaction.

CONCLUSION

Our results support the use of smartphone touchscreens for research into ET, although further studies are required.

Freehand interaction with large displays: Effects of body posture, interaction distance and target size on task performance, perceived usability and workload

The past decade has seen increasing popularity of large display-based freehand interaction. This study examined the effects of body posture, interaction distance and target size on freehand interaction with a large display. Participants performed pointing and dragging tasks by freehand interaction with a large display under sitting and standing postures and at different interaction distances. Targets in both small and large sizes were examined. Results showed that interaction distance yielded a significant effect on error rate, but the effect differed by task type. Little measurable difference was found in interaction performance, perceived usability and workload between sitting and standing postures. There were significant interaction effects between posture and interaction distance on perceived workload. Larger target size led to higher efficiency and accuracy in pointing tasks, but reduced accuracy in dragging tasks. This study provided implications that are likely to improve the design and deployment of large display-based freehand interaction techniques.

Effects of control-to-display gain and operation precision requirement on touchscreen operations in vibration environments

Touchscreen has gained increasing popularity. However, little is known about touchscreen use in vibration environments. This study aimed to examine the effects of control-to-display gain (GAIN) and operation precision requirement on touchscreen operations in varied vibration environments. Twenty participants attended an experiment where they were instructed to perform three types of basic touchscreen operation tasks in static, low vibration, and high vibration environments, respectively. Five GAINs (0.75, 1, 2, 3 and 4) and three operation precision requirements (90%, 95%, and 99%) were examined. The results indicated that vibration exerted adverse effects on task performance, and increased perceived workload, perceived task difficulty and discomfort. Task completion time showed a U-shaped curve as GAIN increased. Lowering operation precision requirement improved task performance and reduced perceived workload, especially in vibration environments and at larger GAINs. The findings provide practical implications on the design of usable touchscreen interfaces in vibration environments.

Examination of touch-coordinate errors of adolescents with unilateral spastic cerebral palsy at an aiming-tapping task

BACKGROUND/OBJECTIVE

This study aimed to investigate performance (touch-coordinate errors, inter-touch interval) of touch screen technology in adolescents with unilateral spastic cerebral palsy (USCP) and healthy peers.

MATERIALS AND METHODS

This prospective case-control study included 31 adolescents. The participants consisted of 15 adolescents with CP in the USCP group and 16 age-matched healthy peers in the control group. All participants performed an aiming-tapping task with an Android tablet. Four sessions were randomly applied: visual feedback (VF) and no VF with the dominant hand's index finger (DHF), and VF and no VF with the non-dominant hand's index finger (NDHF). Inter-touch interval (ITI) and touch-coordinate errors (TCE) were calculated.

RESULTS

There were significant differences between the groups for VF and no VF-NDHF TCE and ITI (respectively p= 0.001, p= 0.01, p= 0.001, p= 0.004) and VF and no VF-DHF TCE values (respectively p= 0.01, p= 0.008). When comparing the dominant and non-dominant hand in the USCP group, there was a significant difference on TCE with no VF (p= 0.01).

CONCLUSION

This study provided insight into the touch screen performance of adolescents with USCP, who performed an aiming-tapping task with a tablet. Results showed that both affected and unaffected hand performance of touch screen tasks was impaired in adolescents with USCP.

A novel approach to bi-objective optimization of touch-screen installation position for minimizing physical workload and increasing screen visibility

The aim of this study was to propose a new method for optimizing the touch-screen installation position in order to minimize the physical workload and increase screen visibility. Ten students participated in this study. The participants utilized a touch screen at different installation heights (50, 65, and 80% of stature), tilt angles (0°, 45°, and 90° from the horizontal plane), and having different button sizes (a square with a side of 10, 20, and 30 mm). The joint angles, when using a touch screen, were measured to calculate the joint torque ratios (JTRs). Subjective screen visibility were also determined. The optimal installation position was determined by solving a bi-objective optimization problem consisting of two objective functions. The Pareto optimal solutions for the two objectives showed a range of 1124-1251 mm and 44.4-67.9°. The proposed method determined the optimal installation position of the touch screens.

Investigation of force, contact area and dwell time in finger-tapping tasks on membrane touch interface

This study aimed to determine the touch characteristics during tapping tasks on membrane touch interface and investigate the effects of posture and gender on touch characteristics variables. One hundred participants tapped digits displayed on a membrane touch interface on sitting and standing positions using all fingers of the dominant hand. Touch characteristics measures included average force, contact area and dwell time. Across fingers and postures, males exerted larger force and contact area than females, but similar dwell time. Across genders and postures, thumb exerted the largest force and the force of the other four fingers showed no significant difference. The contact area of the thumb was the largest, whereas that of the little finger was the smallest; the dwell time of the thumb was the longest, whereas that of the middle finger was the shortest. Relationships among finger sizes, gender, posture and touch characteristics were proposed. The findings helped direct membrane touch interface design for digital and numerical control products from hardware and software perspectives. Practitioner Summary: This study measured force, contact area and dwell time in tapping tasks on membrane touch interface and examined effects of gender and posture on force, contact area and dwell time. The findings will direct membrane touch interface design for digital and numerical control products from hardware and software perspectives. Abbreviations: M: mean; SD: standard deviation; ISO: International Organization for Standardization; LCD: liquid crystal display; ANOVA: analysis of variance; ANSI: American National Standards Institute; HFES: Human Factors and Ergonomics Society.

Interaction with touchscreen smartphones in patients with essential tremor and healthy individuals

INTRODUCTION

Smartphones use in biomedical research is becoming more prevalent in different clinical settings. We performed a pilot study to obtain information on smartphone use by patients with essential tremor (ET) and healthy controls, with a view to determining whether performance of touchscreen tasks is different between these groups and describing touchscreen interaction factors.

METHOD

A total of 31 patients with ET and 40 sex- and age-matched healthy controls completed a descriptive questionnaire about the use of smartphones. Participants subsequently interacted with an under-development Android application, and performed 4 tests evaluating typical touchscreen interaction gestures; each test was performed 5 times.

RESULT

The type of smartphone use and touchscreen interaction were not significantly different between patients and controls. Age and frequency of smartphone use are key factors in touchscreen interaction.

CONCLUSION

Our results support the use of smartphone touchscreens for research into ET, although further studies are required.

Touchscreen interfaces in context: A systematic review of research into touchscreens across settings, populations, and implementations

Although many studies have been conducted on the human factors and ergonomics (HFE) of touchscreens, no comprehensive review has summarized the findings of these studies. Based on a schema (three dimensions of understanding critical for successful display selection) presented by Wickens et al. (2004), we identified three dimensions of analysis for touchscreen implementations: touchscreen technology, setting and environment of implementation, and user population. We conducted a systematic review based on the PRISMA protocol (Moher et al., 2009), searching five article databases for relevant quantitative literature on touchscreens. We found that all three dimensions of analysis have a significant effect on the HFE of touchscreens, and that a selection for or against touchscreens must take into consideration the specific context of system interaction in order to maximize safety, performance, and user satisfaction. Our report concludes with a set of specific recommendations for systems designers considering touchscreens as input/output devices, and suggestions for future study into the HFE of touchscreens.

Examining the Usability of Touch Screen Gestures for Older and Younger Adults

OBJECTIVE

We examined the usability issues associated with four touch screen gestures (clicking, dragging, zooming, and rotating) among older and younger users.

BACKGROUND

It is especially important to accommodate older users' characteristics to ensure the accessibility of information and services that are important to their quality of life.

METHOD

Forty older and 40 younger participants completed four experiments, each of which focused on one gesture. The effects of age, type of touch screen (surface acoustic wave vs. optical), inclination angle (30°, 45°, 60°, and 75°), and user interface factors (clicking: button size and spacing; dragging: dragging direction and distance; zooming: design of zooming gesture; rotating: design of rotating gesture) on user performance and satisfaction were examined.

RESULTS

Button sizes that are larger than 15.9 × 9.0 mm led to better performance and higher satisfaction. The effect of spacing was significant only when the button size was notably small or large. Rightward and downward dragging were preferred to leftward and upward dragging, respectively. The younger participants favored direct manipulation gestures using multiple fingers, whereas the older participants preferred the click-to design. The older participants working with large inclination angles of 60° to 75° reported a higher level of satisfaction than the older participants working with smaller angles.

CONCLUSION

We proposed a set of design guidelines for touch screen user interfaces and discussed implications for the selection of appropriate technology and the configuration of the workspace.

APPLICATION

The implications are useful for the design of large touch screen applications, such as desktop computers, information kiosks, and health care support systems.