• Journal of Electrical Engineering and Technology
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• v.10 no.6
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• pp.2376-2383
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• 2015

Assistance of the operator’s walking ability while carrying a load is a challenging area in lower limb exoskeletons. We implement an exoskeleton called the Unmanned Technology Research Center Exoskeleton (UTRCEXO), which enables the operator to walk with a load more comfortably. The UTRCEXO makes use of two types of DC motor to assist the hip and knee joints. The UTRCEXO detects the operator’s walking intention including step initiation with insole-type FSRs faster without using any bio-signals and precedes the operator’s step with a reference torque. It not only reduces interaction forces between the operator and the UTRCEXO, but also allows the operator to walk with a load more comfortably. In this paper, we present the UTRCEXO implementing the walking assistance mechanism with interaction force reduction during walking.

• Journal of the Ergonomics Society of Korea
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• v.35 no.1
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• pp.39-52
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• 2016

Objective: This paper investigates gait changes according to different heel heights and speeds, and the interaction between the effects of the heel height and the speed during walking on stride parameters and joint angles. Furthermore, the relationship among heel height, speed and gait variables is investigated using linear regression. Background: Gait changes by heel height or speed have been studied respectively, but has not been reported whether there is an interaction effect between heel height and speed. It would be necessary to understand how gait changes when a person wears heels in different heights at various speeds, for example, high-heeled walking at fast speed, since it may cause unusual gait patterns and musculoskeletal disorders. Method: Ten females were asked to walk at five fixed cadences (94, 106, 118, 130 and 142 steps/min.) wearing three shoes with different heel heights (1, 5.4 and 9.8cm). Nineteen gait variables were analyzed for stride parameters and joint angles using two-way repeated measure analysis of variance and regression analysis. Results: Both heel height and speed affect movement of ankle, knee, spine and elbow joint, as well as stride length and Double/Single support time ratio. However, there is no significant interaction effect between heel height and speed. The regression result shows linear relationships of gait variables with heel height and speed. Conclusion: Heel height and speed independently affect stride parameters and joint angles without a significant interaction, so the gait variables are linearly amplified or diminished by the two factors. Application: Walking in high heels at fast speed should be careful for musculoskeletal disorders, since the amplified movement of knee and spine joint can lead to increased moment. Also, the result might give insight for animators or engineers to generate walking motion with high heels at various speeds.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.63-68
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• 1987

In this study, a pantograph leg of the four legged walking vehicle is analysed with regard to mechanical energy consumption. Energy efficiency of the vehicle is estimated in terms of specific resistance varying body height, stride length and walking speed. The interaction between specific resistance and the parameters is investigated.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.570-572
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• 2006

This paper discusses the method of moving object detection for biped robot walking. Most researches on vision based object detection have mostly focused on fixed camera based algorithm itself. However, developing vision systems for biped walking robot is an important and urgent issue since hired walking robots are ultimately developed not only for researches but to be utilized in real life. In the research, method for moving object detection has been developed for task assignment and execution of biped robot as well as for human robot interaction (HRI) system. But these methods are not suitable to biped walking robot. So, we suggest the advanced method which is suitable to biped walking robot platform. For carrying out certain tasks, an object detecting system using modified optical flow algorithm by wireless vision camera is implemented in a biped walking robot.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.427-435
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• 2009

The aim of this study was to examine the effect of a brisk walking intervention for 8weeks on isokinetic muscular function factor(strength, power, endurance). The following results were found from the current study: First, Isokinetic muscle function(strength, power, endurance) on $60^{\circ}/sec$ in extension and flexion was significant exercise group and interaction in left knee flexion and right knee extension(P<.00l). Secondly, Isokinetic muscle function(strength, power, endurance) on $120^{\circ}/sec$ in extension and flexion was significant exercise group and interaction in left knee flexion and right knee extension(P<.001). Thirdly, Isokinetic muscle function(strength, power, endurance) on $180^{\circ}/sec$ in extension and flexion was significant exercise group and interaction in left knee flexion and right knee extension(P<.001). Considering the above result of the study the brisk walking had more improvement knee flexor and extensor muscular power. Therefore the brisk walking in the study can be proposed as effective plan to prevention hurt from a sarcopenia and to raise quality in life.

• Steel and Composite Structures
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• v.30 no.6
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• pp.577-589
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• 2019

In this study, on-site testing was carried out to investigate the vibration performance of a composite steel-bar truss slab with steel girder system. Ambient vibration was performed to capture the primary vibration parameters (natural frequencies, damping ratios, and mode shapes). The composite floor possesses low frequency (< 10 Hz) and damping (< 2%). Based on experimental, theoretical, and numerical analyses on natural frequencies and mode shapes, the boundary condition of SCSC (i.e., two opposite edges simply-supported and the other two edges clamped) is deemed more reasonable for the composite floor. Walking excitations by one person (single excitation), two persons (dual excitation), and three persons (triple excitation) were considered to evaluate the vibration serviceability of the composite floor. The measured acceleration results show a satisfactory vibration perceptibility. For design convenience and safety, a crest factor ${\beta}_{rp}$ describing the ratio of peak acceleration to root-mean-square acceleration induced from the walking excitations is proposed. The comparisons of the modal parameters determined by ambient vibration and walking tests reveal the interaction effect between the human excitation and the composite floor.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
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• 2002.05a
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• pp.273-278
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• 2002

Modern society is an interaction between many different environments. It is important to the mutual relationships between people and especially between people and the environment. One of the mutual relationships between people and the environment is the traffic system, especially the traffic signals which give priority to pedestrian and traffic flow. Traffic signals for the pedestrian on the crosswalk contribute to a safe road environment for the pedestrian, while the traffic signals for the pedestrian running for the flickering of the green signal causes psychological stress. Therefore, this study investigated whether the walking velocity was influenced by the flickering of the green signal or not. Also, this study investigated whether the walking distance had an effect on the walking velocity of the elderly pedestrian or not. It was proved that the flickering of the green signal and the walking distance influenced the walking velocity and subjective sensitiveness according to the result of this study.

• Physical Therapy Korea
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• v.26 no.2
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• pp.16-23
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• 2019

Background: High-heeled shoes can change spinal alignment and feet movement, which leads to muscle fatigue and discomfort in lumbopelvic region, legs, and feet while walking. Objects: This study aimed to identify the effects of different shoe heel heights on the walking velocity and electromyographic (EMG) activities of the lower leg muscles during short- and long-distance walking in young females. Methods: Fifteen young females were recruited in this study. The experiments were performed with the following two different shoe heel heights: 0 cm and 7 cm. All participants underwent an electromyographic procedure to measure the activities and fatigue levels of the tibialis anterior (TA), medial gastrocnemius (MG), rectus femoris (RF), and hamstring muscles with each heel height during both short- and long-distance walking. The walking velocities were measured using the short-distance (10-m walk) and long-distance (6-min walk) walking tests. Results: Significant interaction effects were found between heel height and walking distance conditions for the EMG activities and fatigue levels of TA and MG muscles, and walking velocity (p<.05). The walking velocity and activities of the TA, MG, and RF muscles appeared to be significantly different between the 0 cm and 7 cm heel heights during both short- and long-distance walking (p<.05). Significant difference in the fatigue level of the MG muscle were found between the 0 cm and 7 cm heel heights during long-distance walking. In addition, walking velocity and the fatigue level of the MG muscle at the 7 cm heel height revealed significant differences in the comparison of short- and long-distance walking (p<.05). Conclusion: These findings indicate that higher shoe heel height leads to a decrease in the walking velocity and an increase in the activity and fatigue level of the lower leg muscles, particularly during long-distance walking.

• Structural Engineering and Mechanics
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• v.74 no.5
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• pp.711-722
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• 2020

In this study, on-site testing was carried out to investigate the vibration serviceability of a composite steel-bar truss slab with steel girder system. Impulse excitations (heel-drop and jumping) and steady-state motion (walking and running) were performed to capture the primary vibration parameters (natural frequency and damping ratio) and distribution of peak acceleration. The composite floor possesses low frequency (<8.3Hz) and damping ratio (<2.47%). Based on experimental, theoretical, and numerical analyses on fundamental natural frequency, the boundary condition of SCSS (i.e., three edges simply supported and one edge clamped) is deemed more comparable substitutive for the investigated composite floor. Walking and running excitations by one person (single excitation) were considered to evaluate the vibration serviceability of the composite floor. The measured acceleration results show a satisfactory vibration perceptibility. For design convenience and safety, a crest factor β_rp describing the ratio of peak acceleration to root-mean-square acceleration induced from the walking and running excitations is proposed. The comparisons of the modal parameters determined by walking and running tests reveal the interaction effect between the human excitation and the composite floor.

• Structural Engineering and Mechanics
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• v.83 no.6
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• pp.729-744
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• 2022

In this paper, an analytical formulation is proposed to predict the vertical vibration response due to the pedestrian walking on a footbridge considering the human-structure interaction, where the footbridge and pedestrian are represented by the Euler beam and linear oscillator model, respectively. The derived coupled equation of motion is a nonlinear fourth-order partial differential equation. An uncoupled solution strategy based on the combined weighted residual and perturbation method) is proposed to reduce the tedious computation, which allows the separate integration between the bridge and pedestrian subsystems. The theoretical study demonstrates that the pedestrian subsystem can be treated as a structural system with added mass, damping, and stiffness. The analysis procedure is then applied to a case study under the conditions of single pedestrian and multi pedestrians, and the results are validated and compared numerically. For convenient vibration design of a footbridge, the simplified peak acceleration formula and the idea of decoupling problem are thus proposed.