The purpose of this study was to evaluate the legibility of one-syllable Korean characters with the participation of sixteen subjects. The experiment considered nine factors including age (young and old), gender (male and female), illuminance (150lx and 600lx), viewing distance (50cm and 200cm), material type (paper and LCD), typeface (Ming and Gothic), thickness (plain and bold), color contrast (black letter/white background and white letter/black background), and complexity (simple, complex, and number) to examine main effects with a $2^{6-3}\times3$ fractional factorial design. The dependent variables were minimum character size of 100% correctness, maximum character size of 0% correctness, and minimum character size of comfortable reading preference. The results of analysis of variance (ANOVA) revealed that age, illuminance, viewing distance and complexity were significant for all dependent variables, except gender which was significant only for the minimum character size of comfortable reading preference. In general, the young could see twofold smaller size letters than the elderly. The subjects could see smaller sized letters with the illuminance of 600lx and viewing distance of 50cm than 150lx and 200cm, respectively and also with numbers, simple characters, and complex characters in that order. The findings of this study could be characterized about the legibility of Korean characters and be good resources for developing its standard.

Our study goal is to find out how the table height influences functional ability of upper extremity to patients with stroke when they are having therapy. In this study, we tested forty patients with stroke at the age of over sixty-five who do not have visual, auditory disability and have no difficulty in communicating and moving things by using upper extremity. And they were able to pinch grip in hospital. We used occupational table for occupational therapy as Lab Materials. We also used cube and pegs board to test upper extremity functional ability. We used occupational table for occupational therapy as Lab Materials and we used cube and pegs board to test upper extremity functional ability. The method is that we measured the recommended table height that takes the subjects' size into consideration and patients' preferred table height and therapists' preferred table height and we applied them and then we have done a comparative analysis and set significance level(p<0.05). As the result, we found the Statistically significant between the recommended height and the other two, which are patients' preferred height and therapists' preferred height. We also discovered that functional ability of upper extremity varies significantly depending on each table height. We came to a conclusion that the table height had effects on the upper extremity functional ability of patients with stroke who are over sixty-five years old. It is therefore considered that the proper table height is important to improve upper extremity functional ability of patients with stroke for their physical therapy.

The purpose of this study was to assess activation and contribution of muscles of the elderly according to increased loading during the arm flexion extension resistance exercise. Surface electromyographic signals were acquired from biceps brachii, triceps brachii, deltoid posterior, pectoralis major and latissimmus dorsi to determine the difference of the activation of specific muscles between the elderly and young. Five elderly and five young males with no musculoskeletal disease volunteered for the study. Electromyographic activities in the muscles were measured during resistance exercise and normalized to the maximum EMG activity recorded in the maximal voluntary static contraction (MVC). Against the increased loading during arm flexion/extension resistance exercises, the young uses muscles evenly but the elderly uses one specific muscle frequently. Contribution of triceps brachii during extension and deltoid posterior during flexion was principal in the elderly.

A cross-sectional study was conducted to assess the association between musculoskeletal workload and psychosocial job stress variables from 100 employees from a cable making industry. It was found that the employees who had to do musculoskeletal hazardous tasks suffered higher psychosocial stress in 'decision latitude', 'job insecurity' and 'psychological job demands' also. The employees with higher level of psychosocial job stress in 'psychological job demands' and 'score of the "type A" personality' responded that they had higher 'physical job demands' from the task irrespective of its musculoskeletal hazardousness. These results confirm that musculoskeletal workload were associated with both physical and psychosocial work factors. Attention should be paid to psychosocial work factors along with physical workload to prevent musculoskeletal disorders in the manufacturing industries.

This study investigated perceived discomforts and those reasons of the young and middle-aged, the aged, the disabled and the pregnant in various daily activities, and elicited universal design factors based on human capacities (physical, sensory, cognitive and affective). A total of eighty people (twenty subjects for each user group) participated in one-to-one interviews about thirty six items of daily activities. A degree of discomfort of the daily activities was measured using Borg's CR10 scale. As a result, the disabled and the pregnant complained about almost all of the daily activities, and their degrees of discomforts were significantly higher than those of the youth and middle-aged and the aged. However, the youth and middle-aged and the aged only complained about some specific items. The major reasons of discomforts were related to physical and affective capabilities in general, where the detailed reasons of each user group were comparatively different. Finally, the universal design factors were elicited for each daily activity item based on the results of each user group. This study can be used to understand the discomforts and characteristics of the aged, the disabled and the pregnant in the various daily activities. The universal design factors elicited can also be applied to design related products and facilities universally.

These days mobile phone which were used mainly by grown-up persons are now widely used among children as well due to new social demands. Despite this trend, existing mobile phones are still being designed and produced according to the taste of people in their 20s and 30s, even the elderly, not satisfying physical, emotional and cognitive characteristics raised by children. This study aimed to extract the design factors of mobile phones for children by reflecting functional factors requested by children and parents in QFD's customer demands. First, functional and design factors requested in mobile phones for children were extracted from existing products and documentary records and some functional factors were selected through a process of integration and omission. The survey research was conducted on children and parents, based on the selected functional factors. Based on the survey research, functional factors were analyzed using AHP, and key functional factors considered by children and parents in mobile phones for children were investigated. Finally, in order to reflect the results in QFD, the correlation between functional factors and design factors was constructed as HOQ through experts' evaluation. The results showed that both children and parents recognized the basic functions such as telephoning, text messaging and phone directory as high priority functional factors, even though the relative importance was different between children and parents. Therefore, it is likely to satisfy the desires of both children and parents by designing mobile phones for children in consideration of design factors such as menu depth, button independence and button arrangement. It is expected that this study will promote experiments on design factors and propose basic data for and guidelines to mobile phone design for children.

With increasing needs for affective design, it became an essential part in a product development process to look up quantitative ergonomic data that reflects customers' preferences on design factors in various products. This study looked at wide LCD monitors and analyzed customers' affective preferences regarding monitor's bezel frame size and shape. The monitor's bezel frame depth, size and ratio were selected as independent variables among many design parameters. As dependent variables, customer's subjective preferences were measured. A statistical analysis revealed that monitor's bezel frame depth, size and ratio had significant effects on customer's preferences. Also, it was possible to find a different tendency on affective variables and their levels for 19" and 24" wide LCD monitors. In general, experiments revealed that customers reacted more sensitively in 24" wide LCD monitors to all variables. In 19" wide LCD monitors, only the lower frame bezel size had a significant effect, otherwise, lower, upper and side frame bezels appeared to be effective variables in 24" monitors. In order to reflect customer's affective preferences to new design of wide LCD monitors, this study is expected to provide quantitative ergonomic data and guidelines for the design of wide LCD monitor's bezel frame depth and size.

Effects of dark adaptation have large safety implications. This study was aimed to investigate the effects of varying illuminance and the size of critical detail on visual performance (i.e., time-to-detect) in a dark room environment. While adapting to the dark environment, ten subjects were asked to detect and answer simple numerical expressions under 9 experimental conditions (3 illuminance level $\times$ 3 target size). The ANOVA results revealed that the time-to-detect was significantly affected by both of the illumination level and the size of critical detail. As illumination increased from 10 lux to 20 lux, the time-to-detect was significantly declined. For the size of critical detail, 0.5/min size (i.e., equal to 2 minutes of visual angle) resulted in a shorter time-to-detect, as compared to 0.7/min size (i.e., equal to 1.6 minutes of visual angle). Potential applications of this research include the development of design guidelines for illumination and warning signs in poorly illuminated viewing environments.

This paper objected which prevented the accident occurrence of the related farm work, and developed the evaluation indicators for safety supervision on life environment of farmer and farm work to evaluate the health of farm worker and a musculoskeletal disorders. We selected the evaluation item to 82 items for executing the secondary Delphi investigation and the literature research which composed the farm work relationship specialist conference. We applied the index production of the evaluation indicators to decide the detailed element weight from the element which is farm work, the farm machine and the organization, farm workshop, dangerous substance, and life environment through the AHP techniques. Through the result, we can apply other ergonomic evaluation instrument of farm work field, but also the evaluation indicators for safety supervision on farm work.

This study was conducted to assess exposure to musculoskeletal disorders risk factors in the cooking & housekeeping jobs in hotel work. PATH (posture, activity, tools and handling) method was used for data collection at the 6 hotel settings in different regions across Korea. From 26 workers, a total of 949 PATH observations were obtained. The highest percent time on non-neutral posture was 78% for pinch grip, followed by 74%(wrist deviation), 52%(trunk posture), 37%(shoulder/arm posture), and 30%(neck posture). The highest percent time in the three HAL variables was 47% for HAL-cat2. The percent time of items in relation to both loads with more than 5kg and contact stress was less than 2%. The hotel workers were not exposed to vibration.

A visual stress may provoke migraine, cephalalgia, intervene a long term reading and learning capability and reduce the productivity of a laborer who uses computer for a good while. In this study, a web based screening tool for visual stress was developed, it applied to 72 visually normal young persons in parallel with traditional questionnaire about symptoms of visual stress. To estimate visual stress, It is proposed to measure difference of visual search time of Han Gul characters as targets between visual stressful pattern and non-visual stressful pattern as global background of characters. As a result of test, 5 subjects were screened whose mean visual search time in the stressful pattern with 6 CPD spatial frequency increase significantly more than in none stressful pattern(t-test, one-tailed, p=$1.0407\times10^{-11}$). 2 of them were diagnosed as mild visual stress syndrome in the clinic. None had visual distortion and 50% of subjects had visual discomfort in results of the questionnaire. Correlation between visual search time increase rate and normalized number of visual discomfort may be slight(C. coefficient=0.1355). This study may contribute as a basic research for screening person with migraine, visual reading disabilities and VDT syndrome. It is required to apply the test to visual reading disabilities, migraine with visual distortion and/or visual discomfort as well as normal person for higher reliability of the screening tool.

In this study 1,079 occupational accident reports were used to examine the characteristics and causes of occupational injuries in the small-sized textile companies with less than 50 employees. These data were analyzed in terms of age of injured person, work experience, accident type, injury type, and agency of accident. The results show that there are some patterns: (1) injuries occur more frequently in the 40~49yr age group; (2) about half of all accident occurred during the first year of employment; (3) there is a higher percentage of sick people leaving in the 29~90day range; (4) 'caught in and between objects' represents the leading accident type; (5) the most common type of incidence is related to the machinery; (6) 'lower back injuries' is the leading type of occupational disorder. These results can be used to develop more effective accidental occupational injury prevention programs for small-sized textile industries.

The objective of this paper is to compare two national guidelines on the VDT work management published by Ministry of Labor(MOL) and Korean Standard(KS), and suggest possible modifications of them. The scope of this paper was limited to the desktop type of VDT jobs, excluding laptop environment. In addition, questionnaires were administered to office workers to collect information on the discomfort levels in meeting the MOL Notification. From ergonomic point of view, the most noticeable differences between two guidelines were found with respect to the heights of chairs and desks. In fact, the ranges specified in each guideline were not the same. In the field surveys, it could be known that work environments should be improved.

To inspect the quality of data collected from a large-scale body measurement and investigation project, it is necessary to establish a proper data editing process. The three-dimensional body measurement may have measuring errors caused from measurer's proficiency or changes in the subject's posture. And it may also have errors caused in the process of algorithm expressing the information obtained from the three-dimensional scanner into numerical values, and in the course of data-processing dealing with numerous data for individuals. When those errors are found, the quality of the measured data is deteriorated, and they consequently reduce the quality of statistics which was conducted on the basis of it. Therefore this study intends to suggest a new way to improve the quality of the data collected from the three-dimensional body measurement by proposing a working procedure identifying data errors and correcting them from the whole data processing procedure-collecting, processing, and analyzing- of the 2004 Size Korea Three-dimensional Body Measurement Project. This study was carried out into three stages: Firstly, we detected erroneous data by examining of logical relations among variables under each edit rule. Secondly, we detected suspicious data through independent examination of individual variable value by sex and age. Finally, we examined scatter-plot matrix of many variables to consider the relationships among them. This simple graphical tool helps us to find out whether some suspicious data exist in the data set or not. As a result of this study, we detected some erroneous data included in the raw data. We figured out that the main errors are not because of the system errors that the three-dimensional body measurement system has but because of the subject's original three-dimensional shape data. Therefore by correcting some erroneous data, we have enhanced data quality.

Recently, the frequency in use of electric adjustable bed is going up by an increase in the elderly population. In bad ergonomic design for an electric adjustable bed causes some problems in the aspects of usability and safety. In particular, lots of accidents came from going up or going down an electric adjustable bed. In that case, the height of bed is very important factor for preventing an accident. This problem is related to its anthropometric factors. Therefore we carried out its anthropometric analysis and old people's standing action according the height of electric adjustable bed as an experimental study. As a result, we proposed some anthropometric design criteria and identified the effect of bed height when old people use it.

This study concerned with the characteristics and causes of musculoskeletal disorders (MSDs) for employees aged 50 years or older. In order to do this, based on 8,011 accident analysis reports, we analyzed the differences of characteristics between groups under 50 years and 50 years or more in terms of gender, occupation, duration of employment, part of body, industry, size of business and work-related factors. Results show that the distributions of the injuries aged 50 years or older are statistically different from those of the injuries under 50 years. Also, older employees have high relationship between repetition, or contact stress/vibration and upper extremity MSDs. These findings can be used to develop more effective MSD prevention programs for older employees.

The tactical computer is currently being developed and installed in armored vehicles and tanks for reinforcement. With the tactical computer, Korea Army will be able to grasp the deployment status of our forces, enemy, and obstacles under varying situations. Furthermore, it makes the exchange of command and tactical intelligence possible. Recent studies showed that the task performance is greatly affected by the user interface. The U.S. Army is now conducting user-centered evaluation tests based on C2 (Command & Control) to develop tactical intelligence machinery and tools. This study aims to classify and regroup subordinate menu functions according to the user-centered task performance for the Korea Army's tactical computer. Also, the research suggests an ergonomically sound layout and size of main touch buttons by considering human factors guidelines for button design. To achieve this goal, eight hierarchical subordinate menu functions are initially drawn through clustering analysis and then each group of menu functions was renamed. Based on the suggested menu structure, new location and size of the buttons were tested in terms of response time, number of error, and subjective preference by comparing them to existing ones. The result showed that the best performance was obtained when the number of buttons or functions was eight to conduct tactical missions. Also, the improved button size and location were suggested through the experiment. It was found in addition that the location and size of the buttons had interactions regarding the user's preference.

In this paper ubiquitous health care system that can monitor health condition was implemented through measuring the sensor that is installed in vehicles. Implemented system consists of various wireless sensors and DB server, transmitting information that is sensed in real-time. In addition, through the sensed data based algorithm, the system which couples Web-based JSP program with Flash GUI, providing information as well as emergency service was established.

Although the entrance of house has been identified as a hotspot for older adults' fall accidents, there was not any lift chair to prevent older adults' accidents. In this study, a lift chair was developed to reduce fall accidents that can occur when older adults put on or take off their shoes in the entrance. In order to develop the product, we considered two aspects. Firstly, we considered older adults' anthropometric data to determine the design specification of the product. Also we considered the environmental characteristics of space using the product. In order to overcome the limited spatial freedom and use the entrance space effectively, we took a simplified and folding type for the product.

Korean vowels have special feature such that same vowels do not appear sequentially in a syllable. And two vowels appear with consistent rules. Using this feature, functional key stroke methods are available to Korean computer keyboard. Tapping a key makes diphthong easily. This will be used to Korean computer keyboard design.