• Journal of rehabilitation welfare engineering & assistive technology
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• v.3 no.1
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• pp.49-53
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• 2009

In this paper, we compared wheelchair seating system between wheelchair users with cerebral palsy and spinal cord injuries. Wheelchair seating system is divided into three parts, seating components, seating cushion, and special functions. Seating components are composed of 10 sections, such as headrest, footrest, etc. There are 4 seating cushions including gel, form, hybrid, and air. Also leg elevation, seat elevation, tilt-in-space, reclining, and standing are special function of the wheelchair. There are 10 wheelchair users, 5 with celebral palsy, and 5 with spinal cord injuries who have participated in this study. 10 wheelchair users have been customers of rehabilitation technology center in national rehabilitation center. On the result, SCI group mostly uses headrest, and Humeral blocks (seating components), air cushion (seating cushion), and tilt in space, reclining (special functions). On the other hand, CP group uses adductor, abductor, and pommel (seating components), form cushion (seating cushion), and some of CP group uses reclining (special functions)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.121-123
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• 2002

The design of an air seat cushion for preventing decubitus ulcer includes many design factors such as the even distribution of interface pressure, the minimization of mean and peak interface pressure values, and the reduction of interface shear force and pressure gradient. It involves the anatomic condition of plegia's buttock as well as air pressure in air cells of cushion. As a result, a suitable design of the cushion satisfying the all requirements is a difficult problem. Therefore, an appropriate and effective numerical tool to develop an air cushion orthosis is required. The purpose of the present study was to develop an air seat cushion orthosis having optimized air cells for evenly distributed interface pressure between the buttock and cushion surface. For the purpose, an advanced finite element (FE) model for the design of air cushion was developed. Since the interface pressure and shear force behavior, as well as stress analyses were primary concern, a FE air cell model was developed and verified by the experiments. Then, the interactions of two cells were checked. Also, the human part of the developed numerical model includes every material property and geometry related to buttock and femoral parts. For construction of dimension data of buttock and femoral parts, CT scans were performed. A commercial FE program was employed for the simulation representing the seating process on the orthosis. Then, sensitive analyses were performed with varying design parameters. A set of optimal design parameters was found satisfying the design criteria of the orthosis. The results were utilized to produce a prototype of the orthosis. Experimentally, the buttock interface pressure distributions from the optimized and previous ones were compared. The new seat orthosis showed a significantly improved interface pressure characteristics compared to the most popular one in the market. The new orthosis will be used for the development of the AI(artificial intelligent) controlled seat orthosis fur prevention of decubitus ulcer fur various plegic patients and the elderly.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1974_1975
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• 2009

The chairbound, handicapped person often requires a cushion to distribute the supportive forces over the largest area possible in order to reduce the risk of the development of a pressure sore. Pressure sores are areas of damaged skin caused by staying in one position for too long and can cause serious infections, some of which are life-threatening. When sitting upright, the greatest proportion of body weight is centerd over the ischial tuberosities. So, it is important that comfortable seating and largest distribution of pressure to prevent pressure sores. Therefore, the objective of this study was to develop the physical pressure measurement device and orthodontic chair to prevent pressure sores.

• Journal of the Ergonomics Society of Korea
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• v.33 no.4
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• pp.255-265
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• 2014

Objective: The purpose of this study was to evaluate comfort levels of functional and non-functional chairs using subjective comfort rating, interface pressure measurement, muscle activity measurement, and skin temperature measurement. Background: Chairs are used for a prolonged period of time for sitting in many places such as the office, at university, at school, in industry, and so on. Almost all people use chairs in their everyday life. The functional properties of the chair are associated with comfort. Method: The subjective evaluation contains questions regarding chair comfort which can be rated with five point scale. The body-seat interface pressure was measured using a pressure mat system. The symmetry of sitting was measured using electromyography. The change in body part (thigh and buttock) temperature before and after sitting on a chair was measured with an infrared camera. Results: Participants rated significantly (p < 0.05) higher comfort scores for the functional chair in relation to the buttock and thigh region. Also, the participants felt a better cushion effect in the functional chair. When using the functional chair, lower interface pressure, better thermal comfort, and better symmetry of erector spinae muscle activity were observed. Conclusion: Overall, interface pressure measurement, muscle activity measurement, thermal imaging and subjective comfort score results showed that the functional chair was more comfortable than the non-functional chair. Application: The adopted methodologies could be used to measure the seating comfort of train seats.