• Journal of the HCI Society of Korea
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• v.10 no.2
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• pp.13-19
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• 2015

Display technology has recently made enormous progress. In particular, display companies are competing each other to develop flexible display. Curved display, as a precursor of flexible display, are now used for smart phones and TVs. Curved monitors have been just introduced in the market, and are used for office work or entertainment. The aim of the current study was to investigate whether the curvature of a 42" multi-monitor affects postural control when it is used for entertainment purpose. The current study used two curvature levels (flat and 600mm). Ten college students [mean(SD) age = 20.9 (1.5)] with at least 20/25 visual acuity, and without color blindness and musculoskeletal disorders participated in this study. In a typical VDT environment, each participant played a car racing video game using a steering wheel and pedals for 30 minutes at each curvature level. During the video game, a pressure mat on the seat pan measured the participant's COP (Center of Pressure), and from which four measures (Mean Velocity, Median Power Frequency, Root-Mean-Square Distance, and 95% Confidence Ellipse Area) were derived. A larger AP (Anterior-Posterior) RMS distance was observed in the flat condition, indicating more forward-backward upper body movements. It can be partly due to more variability in visual distance across display, and hence longer ocular accommodation time in the case of the flat display. In addition, a different level of presence or attention between two curvature conditions can lead to such a difference. Any potential effect of such a behavioral change by display curvature on musculoskeletal disorders should be further investigated.

• Journal of the Ergonomics Society of Korea
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• v.25 no.2
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• pp.1-10
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• 2006

In spite of the rapid increase of computer use in our everyday life, not much effort is undertaken to take measures to prevent Musculoskeletal Disorders(MSDs). In this paper, we suggest a movable armrest which would lower the exposure to the MSDs, especially on the vicinity of arm. The aim of this study is to determine whether there are differences in wrist angle variations, forearm muscular loads, comfort and normal performance between the invented movable armrest and a conventional armrest when using a computer mouse. Eight experienced VDU workers performed a standardized simple task set which consists of 15 detailed tasks with each armrest. The wrist angle variations in the right arm were registered by electrogoniometer and the muscle activities in the shoulder, deltoid and two extensors in the forearm were also registered by electromyograph. The subjects rated perceived comfort while performing the tasks with each armrest. Working with the invented armrest, compared to general, gave significantly decreased wrist angle variations at most of the detailed tasks of both biaxial movements. Moreover, as the distance of targets increased, the difference of muscle activities in two different situations trend to be increasing. At the same time, in work with invented armrest, the subjects rated more comfort and they showed decreased normal performances in 8 detailed tasks which were mainly caused by macro moving time.

• 한국정보교육학회:학술대회논문집
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• 2004.08a
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• pp.457-465
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• 2004

한국정보문화진흥원에 따르면 국내 전체 가구 컴퓨터 보급률은 매년 증가하고 있는 추세이며 전체 국민의 인터넷 이용률 및 계층별 인터넷 이용률 모두 매년 증가하고 있어 사회 전반의 정보화가 크게 진전되고 있다. 이로 인한 어린이들의 컴퓨터 사용도 급격하게 늘어나고 있어 이제는 컴퓨터 사용에 따른 시력장애는 단지 어른들에만 해당되는 것은 아니다. 버컬리 대학의 P.Hoenig이 수행한 한 연구는 컴퓨터로 많은 시간을 보내는 어린이와 근시에는 밀접한 상관관계가 있다는 것을 보여주고 있다. 컴퓨터를 사용하는 성인 70% 이상이 컴퓨터 시력 증상(CVS)을 겪고 있으며 이 증상은 걷기 전부터 컴퓨터를 접해온 많은 어린이들에게도 나타날 수 있다는 사실이 밝혀졌다. [1] 한편 컴퓨터가 직접적으로 아이 시력을 떨어뜨리지 는 않으며 어린이들이 컴퓨터를 어떻게 사용하는가에 따라서 시력에 영향을 미친다는 연구결과도 있다. 본 연구는 컴퓨터의 사용시의 여러 요인이 초등학교 고학년 어린이들의 시력에 어떠한 영향을 미치는가를 다각적인 설문조사를 통해 상관관계를 분석한 결과 어린이들의 컴퓨터 사용시간의 증가는 VDT 증후군의 증가와 시력저하로 이어지고 있고, 학부모들의 어린이들의 컴퓨터 사용 대한 무관심도 시력저하의 요인이 되는 것으로 밝혀졌다. 이에 따라 어린이들의 컴퓨터 사용시의 시력보호 방안도 제시하였다.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.13 no.2
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• pp.85-95
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• 2007

Purpose: The purpose of this study was to investigate the prevalence and affecting factors of work-related musculoskeletal disorder (WRMSD) among the directory assistance operators. Methods: One hundred eighty-five female subjects who worked more than one year as directory assistance operators in a telecommunication company were surveyed with self-administered questionnaires. Subjects were divided into disorder and control group by the NIOSH criterion about WRMSD, and then analyzed. Results: One hundred seventy two subjects (93%) had upper extremity symptoms and seventy subjects (37.8%) were WRMSD. the frequency order of the disorder area was the shoulder 60(32.4%), the neck 37(20.0%), the wrist 20(10.8%), the finger 20(10.8%) and the elbow 5(2.7%). It was found that the difference factors of the WRMSD group were education level (p<0.01), stress from the customers (p<0.01), satisfaction about monitor (p<0.05), temperature (p<0.05), noise (p<0.01), ventilation (p<0.001), working time (p<0.05), and recess (p<0.001). Conclusion: Improving working condition and education for the workers to control the stress are necessary to decrease the WRMSD for the directory assistance operators.

• Korean Institute of Interior Design Journal
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• v.19 no.6
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• pp.249-256
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• 2010

For guaranteeing for security of nuclear power plant, ergonomic factors have been applied to design of main control room, core area for management and control of nuclear power plant, but design elements for performance of operators have been ignored. As the behaviors of operators are important for security of nuclear power plant, space design which makes them pleasant psychologically and makes them maintain attention on security equipments ceaselessly is required. Therefore, the purpose of this study is to analyze space characteristics of main control rooms according to regulations of nuclear power plant and general guidelines of space design, and to offer basic data for designing of main control room which makes operators pleasant psychologically and physically. At first, theoretical issues related with design of main control room are reviewed and several premises of space are developed by abstracting design elements from common space and regulations of nuclear power plant and, then integrating each design elements interactively. In short, the improvement of system environment based on human-machine interface space has brought about perceptual, cognitive, and spatial changes and has realized next generation of main control rooms. And, differences and similarities between ordinary space and main control room, which ergonomic sizes and regulations are applied and is VDT environment based on LDP, are discussed in relation to 13 design elements and 17 space premise.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.49-53
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• 2000

Comparing to an Image test chart which printed from computer. Hahn's standard test chart and Chart project test chart propose to make the program of an image test chart in computer. Test type of the test chart should be programed by difference size which was examined Hangul program of Hangul & Computer Co. An image test of visual acuity most decreased among 3 kinds of testing. Testing of Fixation disparity was same between Diplopia test and chart project test chart, so that. Design of test chart could be programed diverse by Hangul program of Hangul & Computer Co.

• Journal of the Ergonomics Society of Korea
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• v.19 no.3
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• pp.13-21
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• 2000

Men perceive and react around him through the five senses. Also men give rise to the human sensibility and maintain his emotion. This study doesn't limit working environment to VDT environment, but considers the universal working environment acquiring information by eyesight stimulation. In case of forming an abnormal veiling reflection we consider the form ; a vertical(25%, 50%, 75%)and a horizontal(25%, 50%, 75%). The results from the subjective evaluation are analyzed by SD(Semantic Differentical methodology)of 5 point scale for visibility and nuisance when an abnormal veiling reflection forms on target. In addition, the results of the objective evaluation are suggested by measuring and analyzing EEG of bio-signal for visual sensitivity. The results of this study can apply to basic data which create a guideline of a visual operation. In particular, it can be designed as an illumination environment concerning an ergonomic factor on visual operations, mental stress such as a visual inspection operation, visual information search operation, etc. As a result, we can expect to reduce the visual nuisance and contribute to the improvement of the performance and the uplift of the competitive power.

• Journal of the Ergonomics Society of Korea
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• v.28 no.4
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• pp.91-99
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• 2009

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.

• Journal of the Ergonomics Society of Korea
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• v.32 no.3
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• pp.273-278
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• 2013

Objective: This study aims to analyze and evaluate fatigue in upper trapezius muscles of adults when inputting text on a smart phone, thereby examining the risk of cumulative trauma disorders in the musculoskeletal system of the upper extremity. Method: Forty-five healthy adults were divided equally into three groups: a smartphone group, a notebook group, and a desktop group. A surface electromyogram was placed on the upper trapezius muscle of each participant, after which they inputted text for ten minutes within an ergonomic setting; their side posture was recorded on video and analyzed. Results: The spectral edge frequency values for the smartphone group, as recorded from the upper right trapezius muscles on the surface electromyogram, showed a significant decrease(p<.05). Regarding the RULA, all three groups had results indicating "action level 2". Conclusion: All three groups had results indicating "action level 2" according to the RULA, which means that additional research on the posture of the participants while performing tasks is necessary, and their posture needs to be corrected. In particular, the smartphone group has the highest levels of fatigue in the upper trapezius muscles, suggesting that the task of inputting text on a smartphone is a high risk for causing cumulative trauma disorders.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.4
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• pp.208-214
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• 2009

In this study, we examined the effects of background and underline on the readability of displayed text. The background was placed on every other line and the underline was done with every line of the text. The effect of adding color to the background and underline was also of primary concern. Twenty subjects were tested on their reading efficiency (i.e. time-to-read and comprehension) and subjective preference of different text format presented on a LCD. Result showed that for the background condition, the background with green format significantly decreased the time-to-read as compared to the format without any background. The results of ANOVA on comprehension and subjective preference were also consistent with this finding. For the underline condition, otherwise, the underline with yellow format yielded higher speed and better comprehension. The results imply that adding background or underlines with appropriate colors can be an additional and useful way of improving text readability.