• Journal of the Ergonomics Society of Korea
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• v.28 no.4
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• pp.125-137
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• 2009

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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.961-962
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• 2009

• Journal of the Korea Safety Management & Science
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• v.18 no.1
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• pp.45-55
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• 2016

In this study we carry out usability evaluation for adjustable electric beds for home care that are used the most by the elderly, and examines dissatisfaction of users. In this sense, we performed an interview with stakeholders including bed users, developers and suppliers to develop usability evaluation contents. In addition, we carried out feasibility and reliability study over evaluation form through usability assessment, and developed usability evaluation indicator.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.6 no.2
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• pp.55-62
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• 2012

In this paper we propose a control system to preserve the interior angle between back section and upper leg section to be larger than 90 degrees using a single limit switch. To design the control system we analyze the kinematics of actuation mechanisms for the back section and the upper leg section, and find out an optimal solution for the controller design. Using a prototype control system we perform experiments to test the controller performance, and show that the interior angle between the back section and the upper leg section is always preserved larger than 90 degree. From the experimental results, we show the proposed control system is feasible to keep the body posture stability.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.5
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• pp.424-431
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• 2007

This thesis proposed H-Bridge Multi-Level Inverter for Fluidized Bed Combustion Boiler Secondary Air Fan in 200MW thermal power plant. The adjustable speed drive systems improve the efficiency in lightly load condition and extend the life span of motor by limiting the over current at starting. H-Bridge Multi-level Inverter is composed of the several series low voltage power cell inverters, which have the independent isolated do link, in each phase. KEPRI(Korea Electric Power Research Institute) has successfully completed to develop, install, and commission H-Bridge Multi-level Inverter(6.6kV, 1MVA). This thesis gives a full detail about H-Bridge Multi-level Inverter, proposed boiler DCS(Distributed Control System) logic, and commissioning test result.