Ji Hyoun Lim

Relationships of Musculoskeletal Disorder Symptoms and Perceived Workload among Hospital Workers

Objective: This study aims to survey the prevalence of musculoskeletal disorders(MSD) among Korean hospital workers and to analyze the relationship of MSD symptoms and workload perceived by workers. Background: Despite of high exposure to the MSD risk factors and high MSD symptom prevalence among health care workers, there were not enough studies of MSD prevalence among the hospital workers. Method: This study designed a survey based on Nordic questionnaire to obtain MSD symptoms and the degree of four perceived workloads: work repetition, urgency, physical exertion and satisfaction. In this survey, 1,846 workers in a hospital participated. The prevalence of MSD was analyzed for each body part, and MSD cases, which were predetermined in this study, were identified. The relationship between the MSD cases and each perceived workload was analyzed using chi-square test. Results: The pain in the shoulder was the most prevalent among the workers as 52%, and the low back(37%) and leg discomfort(36%) followed. The MSD cases, in which degree of pain was more than severe, were also the most prevalent in the shoulder(13%). Female workers had higher rate of MSD cases than the males. Among the four workload variables, the physical exertion was the statistically related to MSD cases for all the body parts. In addition, the others also had significant relation to MSD cases except one or two body parts. Conclusion: This study found that Korean hospital workers had MSD symptoms mainly in the shoulder, low back and legs in order, and the perceived workload surveyed in this study was highly correlated with MSD symptoms. Application: This study provides another evidence that subjective physical exertion perceived by workers is an important factor to explain MSD cases as same as the objective one.

A Study on the Effect of Pre-cue in Simple Reactions on Control-on-Display Interfaces

Objective: This study focuses on the effects of pre-cues informing the location of upcoming visual stimulus on finger movement response in the context of control-on-display interfaces. Background: Previous research on pre-cues focus on attention allocation and motion studies were limited to indirect control conditions. The design of this study aimed to collect data on the exact landing point for finger-tap responses to a given visual stimulus. Method: Controlled visual stimuli and tasks were presented on a UI evaluation system built using mobile web standards; response accuracy and response time were measured and collected as appropriate. Among the 16 recruited participants, 11 completed the experiment. Results: Providing pre-cue on the location of stimulus affected response time and response accuracy. The response bias, which is a distance from the center of stimulus to the finger-tap location, was larger when the pre-cue was given during a one-handed operation. Conclusion: Given a pre-cue, response time decreases, but with accuracy penalized. Application: In designing touch-screen UIs - more strictly, visual components also acting as controllers - designers would do well to balance human perceptual and cognitive characteristics strategically.

Effects of Visual Stimulus on Response Behavior of Control-on-Display Interface

Control-on-display interfaces enable a direct and intuitive manipulation by inducing control directly through the visual stimuli, thereby reducing information-processing stages and improving feed-forward property. The visual information displayed on such devices act not only as visual stimuli but also as controllers. This study investigated the effect of visual stimulus on users’ response behavior while using touch screen. Three characteristics of visual stimulus were investigated: (a) shape of visual stimulus requesting simple tap reaction, (b) contrast between figure and background, and (c) existence of precue on upcoming event. The effects of the selected factors were tested using the response time and the response accuracy measured by 2D deviation vectors. A full factorial experimental design, followed by a multivariate analysis of variance and pairwise comparisons showed that the shift of the center of area from the circumcenter of the stimuli affects the location where fingertip touched, the different background contrast affects both the time and accuracy, and it is confirmed that precue speeds up the response times and improves accuracy in control-on-display interaction.

Conditions of applications, situations and functions applicable to gesture interface

Although there were many studies related to developing new gesture-based devices and gesture interfaces, it was little known which applications, situations and functions are applicable to gesture interface. This study developed a hierarchy of conditions of applications (devices), situations and functions which are applicable to gesture interface. This study searched about 120 papers relevant to designing and applying gesture interfaces and vocabulary to find the gesture applicable conditions of applications, situations and functions. The conditions which were extracted from 16 closely-related papers were rearranged, and a hierarchy of them was developed to evaluate the applicability of applications, situations and functions to gesture interface. This study summarized 10, 10 and 6 conditions of applications, situations and functions, respectively. In addition, the gesture applicable condition hierarchy of applications, situation and functions were developed based on the semantic similarity, ordering and serial or parallel relationship among them. This study collected gesture applicable conditions of application, situation and functions, and a hierarchy of them was developed to evaluate the applicability of the gesture interface.

A Review of Haptic Perception: Focused on Sensation and Application

Objective: The aim of this study is to investigate haptic perception related researches into three perspectives: cutaneous & proprioceptive sensations, active & passive touch, and cognition & emotion, then to identify issues for implementing haptic interactions. Background: Although haptic technologies had improved and become practical, more research on the method of application is still needed to actualize the multimodal interaction technology. Systematical approached to explore haptic perception is required to understand emotional experience and social message, as well as tactile feedback. Method: Content analysis were conducted to analyze trend in haptic related research. Changes in issues and topics were investigated using sensational dimensions and the different contents delivered via tactile perception. Result: The found research opportunities were haptic perception in various body segments and emotion related proprioceptive sensation. Conclusion: Once the mechanism of how users perceives haptic stimuli would help to develop effective haptic interactrion and this study provide insights of what to focus for the future of haptic interaction. Application: This research is expected to provide presence, and emotional response applied by haptic perception to fields such as human-robot, human-device, and telecommunication interaction.

Evaluating Representativeness of Qualitative Text Data in Identifying UX Issues

ABSTRACT With increasing recognition of user experience (UX), it became important to identify UX issues from customers’ opinions expressed in a form of text that is unstructured qualitative data. Since reliability of qualitative data has little been investigated, it requires much time and effort for researchers to define meanings and values from the qualitative data. Therefore, this article proposes a novel approach to measuring the stability of textual data by adopting semantic network analysis, as shown by our analysis on in-depth interview transcripts and online customer review data. Among the semantic networks generated from text, subnetworks were sampled from the original networks until the representativeness of each sample size was determined. Then, similarities between the subnetworks and the original network were calculated by applying a correlation analysis to determine whether stability occurs. The results indicated that variables of word frequency and network-level statistics affect stability of the network. The suggested method will be able to assist in identifying UX issues.

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.

Development of an UX Assessment Model Based on Network Analysis

This paper introduces a novel approach to assess user experience (UX) by calculating relation of concepts based on network analysis. Since it is highly subjective and context-dependent, there was only marginal success in building quantification models for UX. This paper suggested UX assessment model to quantify the satisfaction level of user experience by assuming user values could be represented with network structure and centrality measures. As a case study, gesture interface for TV was investigated. Three core values were able to be identified, and an UX assessment model was proposed. In addition, the model was validated via quantitative study. The quantitative study collected objective and subjective performance measurements which are related to the peripheries of core values. The result revealed that identified user values significantly affected the overall level of satisfaction, whereas normalized link strengths were not much coincided with the correlation coefficients. This study suggested that an UX assessment model can be used to reveal important user values that affect user’s perceived satisfaction.

Comparing Elder Users' Interaction Behavior to the Younger: Focusing on Tap, Move and Flick Tasks on a Mobile Touch Screen Device

Objective: This study presents an observation and analysis on behavioral characteristics of old users in comparison to young users in the use of control on display interface. Background: Touch interface which allows users to control directly on display, is conceived as delight and easy way of human-computer interaction. Due to the advantage in stimulus-response ensemble, the old users, who typically experiencing difficulties in interacting with computer, would expected to have better experience in using computing machines. Method: Twenty nine participants who are over 50 years old and 14 participants who are in 20s years old were participated in this study. Three primary tasks in touch interface, which are tap, move, and flick, were delivered by the users. For the tap task, response time and point of touch response were collected and the response bias was calculated for each trial. For the move task, delivery time and the distance of finger movements were recorded for each trial. For the flick task, task completion time and flicking distance were recorded. Results: From the collected behavioral data, temporal and spatial differences between young and old users behavior were analyzed. The older users showed difficulty in completing move task requiring eye-hand coordination.