• Korean Journal of Applied Biomechanics
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• v.24 no.3
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• pp.249-258
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• 2014

The purpose of this study was to investigate the different patterns of the lower limb between elderly and adult females to reduce the rate of falls. Ten old females(age: $73.1{\pm}2.69yrs$, height: $151.9{\pm}4.82cm$, mass: $57.36{\pm}5.36$) and ten adult females(age: $28\pm}4.76$ yrs, height: $160.6{\pm}6.83cm$, mass: $53.9{\pm}8.44$) were participated in this experiment. The gait motions were captured with Qualisys system and variables were calculated with Visual-3D. The following results were found. The elderly female group showed bigger inclination angle between COM and COP than the adult female group so that the dynamic stability was reduced in walking for the compensation with a bigger stride width. The elderly female group ensure for the necessary forward movement of COM in order to replace the decreased function of ankle and knee joint. If the distance between COM and COP is closer and the energy reduction of a specific joint is reduced, they could prevent the elderly female's falling rate by strengthening of muscles which were related the extension of ankle joint.

• The Journal of Korean Physical Therapy
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• v.23 no.6
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• pp.85-92
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• 2011

Purpose: This study is executed to examine the effects of Korean somatotype on energy consumption and hormone changes during treadmill gait. Methods: The objects of study were a total of 70 university students in their 20s and 30s divided into 7 groups according to somatotype with 10 members each, 4 groups of male (M1, M2, M3, M4) and 3 groups of female (F1, F2, F3). Results: In case of male groups, there was a significant difference in VO2 and VCO2 between group M1, M2 and M3 (p<0.05). There was also a meaningful difference between Phase1 and Phase2, Phase3 and Phase4 in a phase (p<0.01). In case of female groups, there was a meaningful difference in VO2 between F1 and F2, F3 (p<0.01). There was also a significant difference between Phase1 and Phase2, Phase3 and Phase4 in a phase (p<0.01). There was no significant difference in VCO2 among them, but there was a significant difference in it between Phase1 and Phase2, Phase3 and Phase4 (p<0.01). There was equally no significant difference in the concentration of adrenaline and nor-adrenaline among both male and female groups, but such concentration showed meaningful difference before and after exercise (p<0.01). Conclusion: Energy consumption differs according to somatotype. There is a difference in hormone change, indicating that somatotype has effects on the physiological change. Therefore, in future exercise should be executed in more diverse conditions to further study somatotype with energy consumption and the correlations of hormone change.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.9
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• pp.1039-1048
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• 2015

In this paper, we propose an efficient stair locomotion method for a quadruped robot with mechanism of insectile legs using genetic algorithm(GA). In the proposed method, we first define the factors and the reachable region for the stair locomotion. In addition, we set the gene and the fitness function for GA and generate the gait trajectory by searching the landing position of a quadruped robot, which has the minimun distance of movement and the optimal energy stability margin(ESM). Finally, we verify the effectiveness and superiority of the proposed stair locomotion method through the computer simulations.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.6
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• pp.622-627
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• 2014

This paper proposes a new method which improves recognition rate on the gait recognition system using wavelet transform, linear discriminant analysis and genetic algorithm. We use wavelet transform to obtain the four sub-bands from the gait energy image. In order to extract feature data from sub-bands, we use linear discriminant analysis. Distance values between training data and four sub-band data are calculated and four weights which are calculated by genetic algorithm is assigned at each sub-band distance. Based on a new fusion distance value, we conducted recognition experiments using k-nearest neighbors algorithm. Experimental results show that the proposed weight fusion method has higher recognition rate than conventional method.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.2
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• pp.83-88
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• 2006

This paper proposes a method that minimizes the consumed energy by searching the optimal locations of the mass centers of the biped robot's links using Genetic Algorithm. This paper presents a learning controller for repetitive gait control of the biped robot. The learning control scheme consists of a feedforward learning nile and linear feedback control input for stabilization of learning system. The feasibility of learning control to the biped robotic motion is shown via computer simulation and experimental results with 24 DOF biped walking robot.

• The Journal of Korean Physical Therapy
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• v.11 no.2
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• pp.43-50
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• 1999

The purpose of this study was to evaluate the change of the energy consumption when loading to leg of the 60persons who don't have past history of cardiopulmonary and neuromuscular disease, To evaluate the change or energy consumption, heart rate was measured in sitting position for 5minute, during walking for 3minute at for 4.8km on treadmill, and during resting state after walking with 1Kg loading to right ankle, and the other 1Kg loading was added to left ankle and then heart rates were measured in the The results were as follow; 1. PCI value without loading to Ankle were significantly increased compared to 1Kg, and 2Kg. (p<0.05) 2. Female Subjects showed mon increased PCI value in without leading and 2Kg loading compared to male subjects. ( p<0.05) 3. When 1Kg ana 2Ka loading to ankle significantly differences were showed between them. (p<0.05) 4. In the case of 1Kg and 2Kg loading, the difference among age groups was observed and the significant difference among PCI, PCI 1kg, PCI 2kg was showed in the only group that is less than 30 years old. 5. In every PCI condition the difference among height groups was observed and the significant difference among PCI conditions was showed in the only group that is less than 165cm. 6. The difference among weight groups in each PCI condition was not observed, but the significant differences among PCI conditions was showed in every group except the group that h from 60kg to 69kg. These results showed that energy consumption was increased according to loading on the ankle during Sate so weight of orthosis or prosthesis met be considered when choosing them and during gait training with these ones.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.882-887
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• 2008

In this paper, the dependency of energy efficiency on the walking/running pattern and the walking/running period is analyzed though simulations of walk, trot and gallop. A quadruped animal has its own original features in the walking pattern and the walking period for adaptation to the environment. The robot model used in the simulations has three active joints and one passive spring-loaded joint at each leg, which is based on the actual quadruped robot, HUNTER (Hanyang UNiversity TEtrapod Robot), developed in the lab. Also included is the dependency of energy efficiency on the walking period in trot.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.227-235
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• 2012

The purpose of this study was to analysis the effect of form of outsole on lower leg Electromyography (EMG) during gait. The subject were 11 women(mean age $47.33{\pm}4.4$ years, height $158.00{\pm}3.3$cm, weight $59.50{\pm}6.1$, body mass index $23.80{\pm}1.8kg/m^2$), who had no serious foot musculoskeletal disease within3years prior to study. The vastus medialis, gastrocnemius, semitendinosus, tibialis anterior were compared during gait with 2 types of shoe(complex function double rocker sole, negative-heel rocker sole) by using pair t-test(p<.05). The vastus medialis, gastrocnemius, semitendinosus were not found to be significantly different among the 2 types of shoe but tibialis anterior were found(p<.05). The complex function double rocker sole shoe caused a significant change in energy expenditure compared to the negative-heel rocker sole shoe.

• Korean Journal of Applied Biomechanics
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• v.20 no.2
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• pp.191-196
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• 2010

The purpose of this study was to investigate the effect of gait speed and walkway slope on the body acceleration, for the future validation of using an accelerometer in the estimation of energy consumption. Ten young healthy subjects with accelerometers on the upper thigh and ankle walked on a treadmill at 9 conditions(three speeds ${\times}$ three slopes) for 5 minutes. Acceleration signals of four directions, i.e. anterior-posterior(AP), medio-lateral(ML), superior-inferior(SI) and vector sum(VS) directions, of each sensor were measured, and root means squared(RMS) values of them were used as analysis variables. As statistical analysis, repeated measure two-way ANOVA was performed for RMS accelerations at each attachment sites, with slope and velocity as independent factors. At both the upper thigh and ankle, RMS acceleration of all directions were affected by gait velocities(p<.001) showing greater accelerations for higher velocities. Contrary to expectations, no slope effect existed in RMS accelerations at hip. Moreover, RMS acceleraion at ankle decreased with slope in SI and VS directions(p<.01). These results suggests that RMS acceleration cannot reflect the change in physical activity due to the change in walkway slope.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.10
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• pp.1029-1036
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• 2011

An energy-efficient reference walking trajectory generation algorithm is suggested utilizing allowable ZMP (Zero-Moment-Point) region, which maxmizes the energy efficiency for cyclic gaits, based on three-dimensional LIPM (Linear Inverted Pendulum Model) for biped robots. As observed in natural human walking, variable ZMP manipulation is suggested, in which ZMP moves within the allowable region to reduce the joint stress (i.e., rapid acceleration and deceleration of body), and hence to reduce the consumed energy. In addition, opimization of footstep planning is conducted to decide the optimal step-length and body height for a given forward mean velocity to minimize a suitable energy performance - amount of energy required to carry a unit weight a unit distance. In this planning, in order to ensure physically realizable walking trajectory, we also considered geometrical constraints, ZMP stability condition, friction constraint, and yawing moment constraint. Simulations are performed with a 12-DOF 3D biped robot model to verify the effectiveness of the proposed method.