• The Journal of Korean Physical Therapy
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• 제24권6호
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• pp.383-387
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• 2012

Purpose: Rising from a chair is important for activities of daily living. Several factors have influence on sit-to-stand movement. We studied the effect of inclination of seat surface of on the movement of rising from a chair with electromyographic (EMG). Methods: Twelve subjects performed the sit-to-stand movement on anterior-inclined, standard, and posterior inclined chair. We measured onset time of tibialis anterior and rectus femoris with EMG on each inclination chair. Results: The onset time at the anterior-inclined chair is significantly faster than it at the standard chair (p<0.05). And the onset time at the posterior-inclined chair is significantly slower than it at the standard chair (p<0.05). Conclusion: Rising from anterior inclined chair appeared to be more effective than rising from the standard and posterior inclined chair. Therefore, this finding suggests that the selection of set surface inclination must be considered for activities of daily living during rehabilitation.

• 대한인간공학회지
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• 제32권1호
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• pp.145-152
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• 2013

Objective: The aim of this study is to develop an ergonomic office chair that has an alarm function for the unbalanced sitting postures. Background: Contrary to expectation, it is reported that office workers sit on their chairs much more in unbalanced postures during daily work. Even though an office worker uses an ergonomically good-designed chair and begins their work in a good sitting posture, his/her posture is likely to shift to the unbalanced bad posture. Therefore, a posture alarm system would be very helpful in keeping office workers' good postures. Method: We developed a prototype chair with four load cells under a seat pan and one load cell beneath a backrest. Through some experiments, we set the criteria for unbalanced bad postures then implemented the criteria into the alarm system of the prototype chair. The chair called e-BASE chair could detect unbalance postures and show alarms for chair users. We also enhanced back support by developing a step-wised folding backrest. Results: The e-BASE chair showed better performance in interface pressure distributions and balanced posture ratio in VDT work. Conclusion: The ergonomic chair with posture alarm function(e-BASE chair) was developed. It showed better performance in seat pressure distribution and in keeping good posture during office work. Application: The posture alarm system and folding backrest can be applied to the new models of office chair.

• 대한인간공학회지
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• 제33권2호
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• pp.155-165
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• 2014

Objective: The aim of this study is to develop an office chair enabling to keep working at reclined sitting posture. Background: Sedentary workers are supposed to change the posture frequently during long hours of sitting. A reclined sitting position has been recommended to reduce disc pressure. But slumped sitting posture caused by the buttock sliding forward without any adjustment of back reclining is commonly observed. The worker seems to have tendency to change the sitting posture maintaining working condition. We assumed the reason to be their hands movement away from the working space when tilting backward. Method: Slide mechanism allowing seat to move forward was designed to maintain the hand position in working space during reclining. A prototype was manufactured and tilting motion was analyzed using motion capture system. Four experiment chairs were tested including the manufactured prototype chair and three other commercial chairs. Results: A backward movements of the hand position were 13.0mm, 101.7mm, 156.1mm and 139.3mm at the prototype chair, compared to chair B, chair C and chair D, respectively. And the movement was remarkably small at the prototype chair. Conclusion: The developed seat sliding chair allows back tilting maintaining hand position at working space. We expect the user tilting back more often than normal tilting chair during seated work. But further investigation is required to figure out the effectiveness of the developed chair using prolonged working hours. Application: The developed office chair directly affects commercialization.

• 한국가구학회지
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• 제24권3호
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• pp.273-285
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• 2013

The bent wood technique has been used for making the bow, the musical instruments and the wagon wheel, The Winsor chair of England in 1730's was the first Lfurniture product by using this method. This method was spread out by Michael Thonet in Austria after the Industrial Evolution. Early making technique of Winsor chair was relatively easy, but Michael Thonet's bent chair was mass produced by the machine and launched the revolution in the industrial furniture. 20th-Century European furniture designers applied the method of layering and forming plywood to bent chairs, enhanced the function and conformability. The bent chair had a big impact on modern chair design. The bent chair has the formative beauty and convenience from the character of softness and colors of wooden materials and has been developed variously by furniture designers. This study is a new approach to use Dyed-Gathered Wood with various colors and patterns as a material of the bend wood. First, bent wood with the Dyed-Gathered Wood enhances a close texture of wooden material textures instead of coating the surface. Second, flexibility of the bent wood with the Dyed-Gathered Wood enables wood bending techniques. Lastly, the Dyed-Gathered Wood is made with relatively cheap woods, replaces expensive imported woods which cause product price rise. This method enables a material cost saving and a stable supply of material.

• 대한산업공학회지
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• 제25권4호
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• pp.459-465
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• 1999

A new-concept VDT workstation chair with adjustable keyboard/mouse support was proposed to minimize physical discomfort and the risk of cumulative trauma disorders (CTDs) at work sites in this study. First, a three-dimensional human modeling tool $(SAFEWORK^{(R)})$ was used to design the new chair satisfying the anthropometric specifications of Korean population. Second, based upon the result of 3-D graphical simulation, a mock-up chair was constructed with an adjustable keyboard/mouse support directly attached to the chair body. Third, muscle fatigue and subjective discomfort were measured to evaluate the newly developed chair. An experiment was conducted to compare the new workstation chair to the traditional computer chair without keyboard/mouse support. Six volunteer subjects participated in six one-hour word-processing sessions with two different chairs and three different postures. Statistical results indicate that the new-concept VDT chair generally improved subjective comfort level and reduced fatigue in finger flexor/extensor and low back muscle. In conclusion, this new VDT workstation chair is expected to reduce physical discomfort and prevent occupational CTD problems in the long run. Implications of the new design and suggestions for the further development are also addressed.

• The Journal of Korean Physical Therapy
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• 제30권3호
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• pp.96-99
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• 2018

Purpose: The purpose of this study was to determine the effects of a chair backrest on respiratory function after prolonged sitting. Methods: Twenty-four young healthy subjects (12 males and 12 females) volunteered to participate in this study, and were equally allocated to a backrest (n=12) or a without backrest group (n=12). A spirometer was used to measure the respiratory functions of all subjects. Results: The chair with backrest group were significant difference in forced vital capacity (FVC), Forced expiratory volume in 1 second (FEV1), and peak expiratory flow (PEF) after sitting for 1 hour, compared with chair without backrest group (p<0.05). The chair with backrest group showed a significantly decreased in FVC, FEV1, and PEF. Conclusion: Using a chair without a backrest may help to reduce lung function deterioration as compared with a chair with a backrest.

• 대한인간공학회지
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• 제29권1호
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• pp.93-100
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• 2010

In this study, user survey and some experiments were carried out to identify older adults' characteristics and needs for shower chair design. Firstly, the category and design components of shower chair were analyzed through product analysis. Secondly, older adults' needs for shower chair were identified through user interview and observation. Thirdly, experiment to measure older adults' motion, EMG, and body pressure while using shower chair was carried out and then older adults' characteristics for the use of shower chair were identified. Finally, the direction of design for shower chair was proposed to improve older adults' satisfaction.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.376-380
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• 2000

All chairs are uncomfortable in the long run, but some chairs become uncomfortable more rapidly than others, and in any particular chair, some people will be more uncomfortable than others. Comfort will depend upon the interaction of chair characteristics, user characteristics, and task characteristics. In this study, we intend to design the comfortable office chair by investigating the anthropometric and biomechanical aspects for Korean. Therefore, we determine the design dimensions using the analysis of anthropometric data. With these dimensions, we design the chair mechanism of which backrest reclines with increasing chair pan declination. This mechanism allows the back to get adequate support at the correct level for any backrest declination. Also, the lumbar support in the backrest descends with increasing backrest reclining. By using this chair, a considerably better sitting posture can be obtained, and uncomfortable feeling and back pain may be prevented.

• 디자인학연구
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• 제15권4호
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• pp.177-188
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• 2002

빅토리아 시대로부터 오늘날까지 수많은 의자들이 디자인되었다. 토네트의 1859년 No.14의자, 라이트의 1904년 등이 높은 의자, 리트벨트의 1917년 적/청의자, 브로이어의 1925년 와실리 의자, 알토의 1932년 파이미오 의자, 이임즈의 1948년 DAR 의자, 피에로 가티의 1969년 사코 의자, 필립 스탁의 1984년 폰 포겔상 의자, 스텀프의 1992년 에어론 의자, 리틀의 1994년 코트 오브 암((oat of Arms)의자 등 - 의자디자인에서 자신의 이론을 표현할 기회를 가졌던 디자이너들의 리스트는 끝이 없어 보인다. 매킨토쉬(1868-1928), 라이트(1867-1959), 알토(1898-1976)와 같은 건축가들은 인테리어와 건축을 위한 예술적 계획속에 의자 디자인을 포함하였었다. 그러나 의자의 제조업자들이 장인의 영역에서 인더스트리얼 프로세스의 영역으로 이동됨에 따라, 디자이너들은 공학적 지식을 배경으로 현대적 제조 기술의 제한요소내에서 혁신적인 의자 디자인들을 개발하였다. 또한, 기능과 구조의 문제를 넘어서 의자의 기본적인 가치는 과거든 현재든 의자의 특성, 아이디어와 가치에 대한 전달에 있으며 의자에 대한 설득력은 그 수사학상의 명확성과 밀접한 관계가 있어 보인다. 의자는 디자이너들이 시각적으로 말하고 개인적 신념을 선언할 수 있는 이상적인 매체가 되어왔다. 미래에도 의자디자인은 비현실적 디자인과 실용적인 디자인 사이에서 계속 고민할 것이며 이것이 바로 디자이너들이 추구하는 유일한 길이라 하겠다.

• 대한인간공학회지
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• 제33권2호
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• pp.97-108
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• 2014

Objective:The present study is intended to evaluate the usability of a console chair for a weapon locating radar by comparing with different kinds of chair design. Background: Console chairs need to be ergonomically designed to reduce physical workload of operators and improve mission capability; few studies have been reported which systematically evaluate usability of military console chairs. Method: Ergonomic design of a console chair, a bus seat, and an office chair was evaluated in terms of headrest, seatback, seatpan, armrest, and controller on a 7-point scale. Ten males in their 20s and 30s were recruited considering the demographic characteristics of console operators. Results: The satisfaction scores of the console chair for headrest, seatback, and seatpan were significantly higher than those of the bus seat (mean difference [MD] = 0.9) and office chair (MD = 1.3). Meanwhile, the satisfaction scores of the console chair for armrest and controller were significantly lower than those of the office chair (MD = -1.4) and bus seat (MD = -2.2). Conclusion: The armrest and controller of the console chair needs ergonomic improvements for better comfort. Application: The evaluation results of the console chair would be of use for ergonomic console chair design.