• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.142-143
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• 2013

• Journal of the Korea Convergence Society
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• v.11 no.5
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• pp.175-182
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• 2020

The calculation of the optimal trajectory of the stepped top-down robot was made using a genetic algorithm and a computational torque controller. First, the total energy efficiency was minimized using the Red-Cold Generic Algorithm (RCGA) consisting of reproductive, cross, and mutation. The reproducibility condition related to the position assembly of the start and end of the stride and the joints, angles, and angular velocities are linear constraints. Next, the unequal constraint accompanies the condition for preventing the collision of the swing leg at the corner with the outer surface of the stairs, the condition of the knee joint for preventing kinematic peculiarity, and the condition of no moment in safety in the traveling direction. Finally, the angular trajectory of each joint is defined by fourth-order polynomial whose coefficient is to approximate chromosomes. This is to approximate walking. In this study, the energy efficiency of the optimal trajectory was analyzed by computer simulation through a biped robot with seven degrees of freedom composed of seven links.

• Horticultural Science & Technology
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• v.33 no.1
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• pp.133-142
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• 2015

This study aimed to identify the exercise intensity associated with four common physical activities for adults (running, skipping rope, walking, and muscle strength exercises) and two horticultural activities (creating a vegetable bed and garden maintenance). For this experiment, 19 males (mean age: $25.8{\pm}2.3$ years) randomly participated in the activities at a glasshouse at Konkuk University. Each of the six activities lasted for 5 minutes; the subjects rested for 5 minutes during intervals between the activities. A portable metabolic analyzer was used to store the oxygen and energy consumption values obtained upon measurement of each activity. In addition, a wireless heart rate monitor was used to measure the subjects' heart rate. According to the results, the four types of physical activities and two horticultural activities carried out by the subjects are moderate- to high-intensity activities [i.e., $3.8{\pm}0.9$ to $9.9{\pm}2.1$ metabolic equivalents (METs)]. Running ($9.9{\pm}2.1$ METs) and skipping rope ($8.8{\pm}2.2$ METs) were categorized as high-intensity physical activities, whereas creating a vegetable bed ($5.0{\pm}1.2$ METs), walking ($4.9{\pm}0.8$ METs), muscle strength exercises ($4.5{\pm}1.3$ METs), and garden maintenance ($3.8{\pm}0.9$ METs) were classified as moderate-intensity physical activities. The exercise intensities of horticultural activities in this study were similar to those of walking and muscle strength exercises. Therefore, participating in these horticultural activities is expected to garner health benefits similar to those reaped from the physical activities described in the current study.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.1 s.173
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• pp.118-123
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• 2000

Most quadruped walking robots under current research are individually controlling every joint ic make them step or walk according to an integrated strategy. Such methods are characterized by at least one pair of an actuator and a sensor installed per each 'oint so that the robots weigh execssively and move inefficiently in terms of energy expenditure. In addition, the task of controlling all the joints simultaneously is quite complex and prone to destabilize the robot motion. These respects keep the existing walking robots away from realistic applications such as transportation even if they have potentially, outstanding adaptability to swamps or uneven terrains as opposed to wheeled vehicles. So, this paper presents a new conceptual quadruped robot developed to walk and steer only with a minimal number of actuators owing to a closed-chain mechanism. To prove its actual performance including the adaptability to various types of terrains. experiments are done with the mammal-type prototype. And. it is also shown that the same concept can be easily extended to carry out different gait forms. for instance, that of spiders only with minor modifications.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2493-2503
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• 2018

Passive dynamic walking exhibits humanoid and energy efficient gaits. However, optimal design of passive walker at multi-variable level is not well studied yet. This paper presents a Chaotic Particle Swarm Optimization (CPSO) algorithm and applies it to the optimal design of flexible passive walker. Hip torsional stiffness and damping were incorporated into flexible biped walker, to imitate passive elastic mechanisms utilized in human locomotion. Hybrid dynamics were developed to model passive walking, and period-one gait was gained. The parameters global searching scopes were gained after investigating the influences of structural parameters on passive gait. CPSO were utilized to optimize the flexible passive walker. To improve the performance of PSO, multi-scroll Jerk chaotic system was used to generate pseudorandom sequences, and chaotic disturbance would be triggered if the swarm is trapped into local optimum. The effectiveness of CPSO is verified by comparisons with standard PSO and two typical chaotic PSO methods. Numerical simulations show that better fitness value of optimal design could be gained by CPSO presented. The proposed CPSO would be useful to design biped robot prototype.

• Journal of Korea Multimedia Society
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• v.21 no.8
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• pp.982-990
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• 2018

In recent years, many wearable devices and mobile apps related to life care have been developed, and a service for measuring the movement during walking and showing the amount of exercise has been provided. However, they do not measure walking in detail, so there may be errors in the total calorie consumption. If the user's behavior is measured by a multi-axis sensor and learned by a machine learning algorithm to recognize the kind of behavior, the detailed operation of walking can be autonomously distinguished and the total calorie consumption can be calculated more than the conventional method. In order to verify this, we measured activities and created a model using a machine learning algorithm. As a result of the comparison experiment, it was confirmed that the average accuracy was 12.5% or more higher than that of the conventional method. Also, in the measurement of the momentum, the calorie consumption accuracy is more than 49.53% than that of the conventional method. If the activity recognition is performed using the wearable device and the machine learning algorithm, the accuracy can be improved and the energy consumption calculation accuracy can be improved.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2012.06a
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• pp.206-207
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• 2012

We need to develop intelligent smart card made unskilled general public's to the shelter on Passenger Ship. prior to development, we have to study passenger of characteristic. so we researched about domestic unskilled general public's of walking speed in refuge situation.

• Journal of Korean Physical Therapy Science
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• v.13 no.3
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• pp.65-75
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• 2006

This study was to find out whether MBT shoes were more effective than general sporting shoes on the kinematic physiology. We comparatively analyzed energy consumption, heart rates, rating of perceived exertion, lactic acid density in blood and muscle activity with EMG. The subjects were 10 regular students of K Univ.(5 male and 5 female). They wore the general sporting shoes for stage 1(group 1), the MBT walking shoes for stage 2(group2) under the same conditions. There was one week interval between stages. 1. There was no significant difference in the energy consumption and the heart rates between two groups. Group 1 showed a higher energy consumption and heart rates than Group 2 under the speed of 4.0 mph. On the other hand, Group 2 showed higher ones over the speed of 4.0 mph. 2. There was no significant difference in the rating of perceived exertion and lactic acid density in blood between two groups. But Group 2 showed a lower fatigue strength than Group 1. 3. Group 2 showed a higher muscle activity with EMG than group 1, especially at the speed of 2.0, 2.5, 3.0, 3.5 mph in quadratus lumborum muscle and at 4.0mph in tibialis anterior muscle. In conclusion, we are less tired in MBT shoes than in general sporting shoes. Also, we can dorsiflex better in the ankle joint, straighten the lumbar region well and walk erect in MBT shoes. Specially, when it walks slowly, it is favorable in an erection walk and when it walks quickly, we have advantage of obesity management.

• Journal of the Korean Society of School Health
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• v.29 no.3
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• pp.218-225
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• 2016

Purpose: The purpose of this study was to investigate the factors affecting energy drinks consumption among adolescents in South Korea. Methods: The study is a secondary analysis. Using statistics from the 11th (2015) Korea Youth Risk Behavior Web-based Survey, any variations among the subjects were presented as percentages and analyzed by $x^2$ test and logistic regression analysis. The study sample comprised 68,043 middle and high school students in South Korea. Results: In Model 1 including general characteristics, the significant factors of energy drinks consumption were gender, weekly allowance, cohabitation with family. and economic status. In the final model where health-related characteristics were added, the significant factors were gender, school type, weekly allowance, cohabitation with family, stress level, sadness, drinking, smoking and walking days. Conclusion: The result suggests that intensified education on energy drinks consumption is needed not only at schools, but in the whole community. Also, adolescents' awareness of potential health effects of energy drinks, in particular when mixed in alcoholic beverages, should be increased through health education.

• Journal of Biomedical Engineering Research
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• v.27 no.6
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• pp.301-309
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• 2006

The main purpose of this study is to derive a regression equation that predicts the individual differences in activity energy expenditure (AEE) using accelerometer during different types of activity. Two subject groups were recruited separately in time: One is a homogeneous group of 94 healthy young adults with age ranged from $20\sim35$ yrs. The other subject group has a broad spectrum of physical characteristics in terms of age and fat ratio. 226 adolescents and adults of age ranged from $12\sim57$ yrs and fat ratio from $4.1\sim39.7%$ were in the second group. The wireless 3-axis accelerometers were developed and carefully fixed at the waist belt level. Simultaneously the total calorie expenditure was measured by gas analyzer. Each subject performed walking and running at speeds of 1.5, 3.0, 4.5, 6.0, 6.5, 7.5, and 8.5 km/hr. A generalized sensor-independent regression equation for AEE was derived. The regression equation was developed fur walking and running. The regression coefficients were predicted as functions of physical factors-age, gender, height, and weight with multivariable regression analysis. The generalized calorie estimation equation predicts AEE with correlation coefficient of 0.96 and the average accuracy of the accumulated calorie was $89.6{\pm}7.9%$.