• 한국정밀공학회지
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• 제27권5호
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• pp.102-111
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• 2010

This paper presents a design of seat mechanism for multi-postures controllable wheelchair. The possible seat postures are reclining, tilting, standing, which are controlled by four seat mechanisms using four linear actuators. The seat mechanisms designed in this study are reclining, tilting, forward-tilting, and elevation mechanism. Three postures except standing are controlled by corresponding mechanisms, but the standing posture is performed by combination of the reclining and the forward-tilting mechanism. Posture control system is composed of PID controllers and a planner to determine a feasible posture based on a posture transition diagram. Simulation results show that the seat mechanism and its control system are applicable to a multi-postures controllable wheelchair.

• 한국소음진동공학회논문집
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• 제20권6호
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• pp.577-582
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• 2010

The squeak propensity in the gear box of an automotive seat system is investigated analytically. The mating parts in the gear box are the lead screw and the nut, where the friction stresses are exerted on the thread of the screw. The lead screw is modeled as a circular beam allowing the bending and torsional vibrations. In the system, the lead screw converts rotating to translating motion so that it moves the automotive seat slightly tilted on the floor. The tilting angle is considered one major parameter in this study. Therefore, the equations of motion associated with the non-conservative friction force are derived with the inclusion of the tilting angle. It is found that the squeak noise corresponds to the several bending modes of the lead screw and its propensity is increased by the tilting angle of the seat.

• 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.

• 대한인간공학회지
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• 제30권2호
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• pp.357-363
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• 2011

Objective: The aim of this study is to set the design direction of the lift chair's tilting seat for development. Background: Great attention has been shown to the development of senior friendly product, because of increasing elderly population rapidly in Korea. Therefore, we need to study on sit-to-stand(STS) motion of elderly systematically for developing lift chair that is one of senior friendly products. Method: In this study, we analyzed joint moment(knee, hip) and muscle activity (Erector spinae, Rectus femoris, Vastus lateralis) on STS motion of elderly(female, 60~70: 7) and young people(female, 20~30: 7) using 3 dimension motion capture camera, force plate, wireless EMG. Results: The results of muscle activity showed a similar trend but the results of joint moment were a lot of differences between the young and the elderly. Conclusion: The results of knee joint moment suggest the angle(10~30deg)-adjustable seat that can be better than to find the optimal seat's angle. Application: The method and results of this study are expected to develop senior friendly product and verification as well as be available to various application.

• 품질경영학회지
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• 제29권3호
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• pp.151-165
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• 2001

The purpose of this study is to develop systematic methods for evaluating the suitability of a seat and build an empirical model for predicting the suitability of a seat. The following research schemes were pursued to achieve the objectives - Development of suitable chair dimensions - Analysis scheme for decomposing the human-product interface system - Development of model for evaluating suitability. As a result, we uncovered six dominant suitability dimensions for the design of a comfortable seat that is related to the physical dimension of a body, Here, six suitability dimensions were identified as the dimensions that represent the human sensitivity and psychological feeling on comfortable seats. Also, 43 human-interface elements (HIE's) such as seat height, seat width, seat depth, tilting angle, seat surface etc. were investigated. HIE was generally defined as the physical characteristic of manufacturing goods, and it had close related to the body dimension of a user and environment that it was used.

• 동양고전연구
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• 제62호
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• pp.263-289
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• 2016

춘추전국시대에 활동한 공자는 수많은 어록을 남기면서 제자를 양성한 교육자이며 한중일 지식인의 존경을 받아 온 대표적인 성현이다. 공자의 행적 및 제자와 경험한 재미있는 에피소드는 그림과 조각 등으로 다양하게 시각화되었다. 특히 공자와 그의 제자 자로가 노나라 환공의 묘에서 기기(?器)를 발견하고 중용의 원리를 터득하여 '좌우명(座右銘)'으로 삼았다는 일화는 조선 왕실을 비롯한 문인들에게 꾸준히 사랑을 받으며 그림으로 표현되었다. 이 일화를 담은 기기도는 그릇만 표현한 정물화와, 공자가 기기를 관찰하는 사건을 그린 인물화로 분류된다. 전자는 백성을 공평하게 다스리고 행동거지를 바로하기 위한 중용의 척도로, 후자는 공자의 일생을 표현한 성적도에 포함되어 교육용 시각물로 활용되었다. 그러나 공자가 기기를 관찰하는 장면은 단독 장르로 독립하거나 인물화 병풍에 수록되었다. 공자의 다른 일화가 도(道)의 계보를 시각화 한 화첩에 포함된 반면, 공자가 기기를 관찰하는 장면은 풍류와 서화 골동 감상을 즐기는 문인들을 그려 모은 병풍에 포함된 것이다. 이렇듯 기기도는 공자의 일화를 그린 인물화의 기능과 상징성을 여러 각도로 알려주는 그림이라 할 수 있다. 기기도의 형식을 분류하고, 시대와 목적에 따라 변화하는 조형성을 분석하여 공자의 일화를 그린 그림들의 다양한 면모를 규명하고자 하는 이 글을 통해 옛 성현의 이야기를 재현하는 방법과 감상 코드에 따른 표현상의 차이가 파악될 것이다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.327-328
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• 2006

In generally, under the influence of over-pressure drop, serious problems such as cavitation, choked flow, flashing and vibration has been coming around the tilting disk check valve. A PIV experiment to examine the cause of energy loss has been performed and the improvement configuration of valve seat based on this visualization results is proposed. In the visualization results, flows in the piping system became instability under the influence of the shape of boss. This unstable flows induces sudden pressure drop in the piping system. So, we change the configuration of boss as a streamlined design to be stabilized the flows. A pressure measurement has been performed to know that the influence of the configuration change. In result, the rate of pressure loss reduction is about 22% at the position of No. 2 and 24.2% at the position of No. 6 in comparison with pre-improved shape.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.577-582
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• 2003

In generally, under the influence of over-pressure drop, serious problems such as cavitation, choked flow, flashing and vibration has been coming around the tilting disk check valve. A PIV experiment to examine the cause of energy loss has been performed and the improvement configuration of valve seat based on this visualization results is proposed. In the visualization results, flows in the piping system became instability under the influence of the shape of boss. This unstable flows induces sudden pressure drop in the piping system. So, we change the configuration of boss as a streamlined design to be stabilized the flows. A pressure measurement has been performed to know that the influence of the configuration change. In result, the rate of pressure loss reduction is about 22% at the position of No. 2 and 24.2% at the position of No. 6 in comparison with pre-improved shape.

• 산업경영시스템학회지
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• 제41권3호
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• pp.108-114
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• 2018

One of the most performed action in daily life is standing up from sitting position. As the population of the world is aging at the high rates, people may face problems with reduced muscle strength as well as psychological changes. This can lead elderly people having difficulties with standing up from chair. Now, with the aging trend worldwide, products are being developed that can support the lives of the elderly. This study examines the distribution of hip pressure in relation to the seating positions of the standing assistance seats under development to prevent standing up accidents in older adults. The currently developing standing assistant chair designed to tilt to a maximum angle of 25 degrees. At over $25^{\circ}$, design considers that older people are at risk of thrown back out of that force and that the forces exerted on their arms and legs can be a significant burden to older people. By considering danger of higher than $25^{\circ}$ for older people which is experimented in the basis of static capturing approach in previous papers, it is experimented people with age group of 20~60 on $0^{\circ}$ to $25^{\circ}$ tilting angle on the basis of dynamic capturing method in order to pick convenient angle of inclination. Moreover, tried to find the optimum angle by comparing the hip pressure distribution when seated at the edge of the seat and at the center of the seat with the pressure distribution sensor.

• 대한기계학회논문집B
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• 제39권6호
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• pp.535-540
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• 2015

등판이 기울어지는 사무용 의자에서 등판 회전축 위치를 인체의 엉덩관절에 일치시키면 인체와 등판이 일체화되어 기울어짐으로써 사용성을 향상시킬 수 있다. 그러나 등판 힌지가 외부로 돌출되지 않도록 하기 위해 적용되는 핀인슬롯 조인트에서 기구적인 마찰이 발생해 등을 기울이고 세우는 동안 사용자에 영향을 줄 것으로 예상된다. 본 연구에서는 마찰 정도가 다른 조인트 부품으로서 슬라이더, 롤러 그리고 베어링 세 가지 유형을 적용하고, 등판 기울임 시 대비 복귀 시의 반발력 비율을 측정하였다. 실험 결과 베어링, 롤러, 슬라이더를 적용한 경우 등판 반발력 비율은$[{\pm}SD]$은 각각 $59.7[{\pm}10.3]%$, $47.2[{\pm}13.6]%$, $30.3[{\pm}18.1]%$로 나타나 베어링을 적용할 경우 마찰이 가장 작았다. 그러나 각 부품들은 생산단가 측면에서 차이를 보이기 때문에 부품 선정 시 마찰감소 성능뿐만 아니라 사용자의 주관적인 만족도를 함께 고려할 수 있음을 제시하였다.