• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.181-182
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1303-1304
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• 2011

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.1
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• pp.65-72
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• 2016

In this study, a fully active transfemoral prothesis with a knee joint is designed considering stair walking conditions. Since the torque at the knee joint required for stair walking condition is relative high compared with the one in normal walking condition, the proposed design has high torque generating mechanism. Moreover, the transfemoral prothesis is designed in compact size to reduce its weight, which is related to comfortable fit and fatigue of patients. Flat type BLDC motor is used for simple and compact structure and various components are used to generate required torque with target working angle and speed. The weight reduction of structure is carried out using optimization method after the initial design process is complete. The optimization is conducted under the load conditions of stair walking. The optimized design is validated via finite element analysis and experiments. As a result, the weight is reduced using topology and shape optimization but maintaining the safety of structure. Also the space efficiency is improved due to its compact size.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.4
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• pp.362-366
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• 2014

In recent years, a permanent magnet linear synchronous motor (PMLSM) has been used in various kinds of transportation applications for its relative high power density and efficiency. The general transportation system arranges the armature on the full length of transportation lines. However, when this method is applied to long distance transportation system, it causes increase of material cost and manufacturing time. Thus, in order to resolve this problem, we suggested stationary discontinuous armature PMLSM. However, the stationary discontinuous armature PMLSM contains the edges which always exist as a result of the discontinuous arrangement of the armature. These edges become a problem because the cogging force that they exert bad influences the controllability of the motor. Therefore, in this paper we proposed the combination of skewed magnets and stair shape auxiliary teeth to reduce the force by edge effect. Moreover, we analyzed the influence of the design factors by using a 3-D finite element method (FEM) simulation tool.

• The Journal of Korea Robotics Society
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• v.4 no.4
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• pp.265-272
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• 2009

IVarious driving mechanisms to adapt to uneven environment have been developed for many urban search and rescue (USAR) missions. A tracked mechanism has been widely used to maintain the stability of robot's pose and to produce large traction force on uneven terrain in this research area. However, it has a drawback of low energy efficiency due to friction force when rotating. Moreover, single tracked mechanism can be in trouble when the body gets caught with high projections, so the track doesn't contact on the ground. A transformable tracked mechanism is proposed to solve these problems. The mechanism is designed with several articulations surrounded by tracks, used to generate an attack angle when the robot comes near obstacles. The stair climbing ability of proposed robot was analyzed since stairs are one of the most difficult obstacles in USAR mission. Stair climbing process is divided into four separate static analysis phases. Design parameters are optimized according to geometric limitations from the static analysis. The proposed mechanism was produced from optimized design parameters, and demonstrated in artificially constructed uneven environment and the actual stairway.

• Physical Therapy Rehabilitation Science
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• v.10 no.1
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• pp.32-39
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• 2021

Objective: The weakness of muscle strength due to stroke affects the posture control and gait in the patients with stroke. Stroke This study examined the effects of the stair climbing training with functional electrical stimulation on muscle strength, dynamic balance, and gait in individuals with chronic stroke. Design: Randomized controlled trial. Methods: Total forty-eight patients were randomly assigned to the 3 groups. Participants randomly divided to stair climbing training with functional electrical stimulation group (SCT+FES group, n=16), stair climbing training group (SCT group, n=16) and control group (n=16). Subjects in the SCT+FES group and SCT group performed stair walking training with and without functional electrical stimulation for 30 minutes, 3 sessions per week for 4 weeks and all subjects received conventional physical therapy for 30 minutes with 5 sessions per week for 4 weeks. Outcome measurements were assessed using the sit-to stand Test for strength, timed up and go test and modified-timed up and go test for dynamic balance, and 10m walk test and GaitRite system for gait. Results: In the SCT+FES group, subjects have been shown the significant increase in lower extremity strength (p<0.05), significantly improve in dynamic balance (p<0.05), and significantly improve in their temporal gait parameter (p<0.05). The SCT+FES group was significantly better than other groups in all parameters (p<0.05). Conclusions: This result suggested that the SCT+FES may be effective strategy to improve muscle strength, dynamic balance, and gait for individuals with chronic stroke.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.301-306
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• 2009

High strength steels are widely used for lightweight automobile parts and the control of springback is very important in sheet metal forming. The object of this study is to develop the forming process for stair type side sill made of high strength steel, DP780. Stair type side sill with local formed area and geometry change area can improve stiffness and design freedom but there are a few studies for forming process. The forming technology considered in this paper is form type process, which have many advantages for farming of high strength steel compared with draw type process. Finite element analysis is carried out to predict formability and springback. It is shown that angle calibration of die is essential for reducing springback, and local forming involving bead is effective to control springback also. The effectiveness of local forming and angle calibration is verified by experimental.

• The International Journal of Costume Culture
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• v.13 no.2
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• pp.154-159
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• 2010

Various decorative patterns and sculptures found in antique architectures like palace architecture and temple architecture are not only valuable assets of our culture but have religious meaning at the same time and show aesthetic aspiration and desire of Korean people. In this study, potential application of patterns in textile industry is suggested based on the reconstructed and patternized geometric patterns of window grids, a decorative element in architecture, and stair and stair somaetdol, a architectural element in Buddhist temples, using Photoshop and Illustrator program of Adobe INC AND Tex-pro program of Youngwoo CNI INC. All around the world today, efforts to reinterpret unique and antique architectures and cultural assets in a modern way has been increasing. Decorative patterns displayed in Buddhist temple architectures which are antique Korean architectures have excellent geometric aesthetic value. And the development potential of patternizing these elements into modern designs is high. Therefore, it is thought to be possible to develop high value-added fabric and to develop various fashion items including apparel and interior decoration based on modern reinterpretation of patterns of window grid and decorative elements of stairs and stair somaetol that are part of our antique architectures.

• Transactions of Materials Processing
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• v.18 no.8
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• pp.601-606
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• 2009

High strength steels are widely used for lightweight automobile parts and the control of springback is very important in sheet metal forming. The object of this study is to develop the forming process for stair type side sill made of high strength steel, DP780. Stair type side sill with local formed area and geometry change area can improve stiffness and design freedom but there are few studies for forming process. The forming technology considered in this paper is form type process, which has many advantages for forming of high strength steel compared with draw type process. Finite element analysis is carried out to predict formability and springback. It is shown that angle calibration of die is essential for reducing springback, and local forming involving bead is effective to control springback also. The effectiveness of local forming and angle calibration is verified by experimental.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.2
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• pp.135-143
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• 2011

Purpose: The purpose of this study was to investigate onset timing of vastus medialis oblique(VMO) relative to vastus lateralis(VL) the VMO/VL electromyographic(EMG) ratio according to heel height Methods: A repeated measures design was used. Fifteen healthy female college students with no known knee musculoskeletal dysfunction were recruited this study. They carried out a standardised stair acent activity under 4 conditions; barefoot, and with heel height of 1, 3, 7 cm. Muscle activity was measured by surface EMG (Myosystem 1400A, Noraxon Inc., U.S.A). Data were analysed using $1{\times}4$ repeated measures ANOVA. Results: Onset timing differed with heel height(p<.05). However, the VMO/VL EMG ratio was not significantly difference between conditions. Conclusion: We found that 7 cm heel height delayed in VMO onset compared with 3 cm heel height during stair ascent, but no change in the relative EMG intensity of VMO and VL as measured by th VMO/VL ratio. The findings indicate that high-heeled shoes may have disadvantages in knee stability because of delayed onset of VMO. Due to a lack of knee joint stability, wearing of high heeled shoes should be avoided.