• Journal of Biomedical Engineering Research
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• v.18 no.1
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• pp.71-78
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• 1997

Kinematic and kinetic studies were performed to investigate the walking characteristics on a treadmill with various slopes at the same speed of 1.25m/sec. Six different slopes of the treadmill were selected . -4%(-$2.3^{\circ}$), 0%($0^{\circ}$), 5%($2.9^{\circ}$), 10%($5.7^{\circ}$), 15%($8.6^{\circ}$), and 20%($11.3^{\circ}$). With increased slopes of the treadmill, both hip and knee flexion angles significantly increased at initial contact, and the maximum hip flexion during swing phase and the maximum knee flexion during stance phase also significantly increased Ankle dorsiflexion angle at initial contact and the maximum dorsiflexion increased with increased slopes. However, the maximum plantarflexion in early swing was slightly reduced with increased slopes. Hip extension in late stance and the maximum knee flexion in early swing was not changed sigilificantly with increased slopes. As for the vertical ground reaction force, compared to the yond level walking, both the first and the second peak forces increased, but the mid-support force decreased.

• Steel and Composite Structures
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• v.13 no.2
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• pp.139-155
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• 2012

Serviceability rather than strength is the most critical design requirement for vibration-vulnerable floor constructions. Annoying vibrations due to normal walking activity have been observed more frequently on long-span lightweight floor systems in office and commercial retail buildings, raising the need for the development of floor vibration design procedures. This paper highlights some limitations of one of the most commonly used guidelines AISC/CISC DG11, and proposes improvements to this method. Design charts and approximate closed form formulas to estimate the walking response are developed in which various factors relating to the dynamic characteristics of both the floor and the excitation are considered. The accuracy of the proposed formulas and other proposals found in the literature is examined. The proposed modifications would be significant, especially with long-span floors where vibration levels may be underestimated by the current design procedure. The application of the proposed prediction method is illustrated by worked examples that reveal a good agreement with results obtained from finite element analyses and experiments. The presented work would enhance the accuracy and maintain the simplicity and convenience of the design guideline.

• Journal of Biomedical Engineering Research
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• v.40 no.6
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• pp.235-241
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• 2019

The purpose of this study was to investigate the effect of the body temperature peripheral circulation with vibration shoes in healthy 10 adults. The magnetic vibration device with non-electric power was mounted in the midsole of the vibration shoes. The experiment was divided into two groups: vibration shoes and no vibration shoes. Subjects were randomly selected and measured body surface temperature by digital infrared thermal imaging (DITI) and non-invasive capillaries change by nailfold microscope (NFM). After walking in a treadmill for 15 minutes at 4.0 km/h speed wearing normal shoes or vibration shoes, DITI and NFM were measured. The walking with vibration shoes showed the body surface temperature shift from the proximal to the distal. In addition, the diameter of the nailfold capillary in the vibration shoes group was thicker and clearer due to the increased blood flow than that of the no vibration shoes group. The vibration shoes are easy to apply to anyone who can walk because it can give vibration stimulation by walking without additional time, cost, and effort in daily life. Further studies are needed to explain the physiological effects of vibration frequency and intensity on the long-term perspective of target subjects resulting from vascular dysfunction.

• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.632-637
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• 2017

Even though the potential for an accident in nuclear power plants is very low, multiple emergency plans are necessary because the impact of such an accident to the public is enormous. One of these emergency plans involves a robotic system for investigating accidents under conditions of high radiation and contaminated air. To develop a robot suitable for operation in a nuclear power plant, we focused on eliminating the three major obstacles that challenge robots in such conditions: the disconnection of radio communication, falling on uneven floors, and loss of localization. To solve the radio problem, a Wi-Fi extender was used in radio shadow areas. To reinforce the walking, we developed two- and four-leg convertible walking, a floor adaptive foot, a roly-poly defensive falling design, and automatic standing recovery after falling methods were developed. To allow the robot to determine its location in the containment building, a bar code landmark reading method was chosen. When a severe accident occurs, this robot will be useful for accident condition monitoring. We also anticipate the robot can serve as a workman aid in a high radiation area during normal operations.

• Physical Therapy Rehabilitation Science
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• v.4 no.1
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• pp.32-37
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• 2015

Objective: This study was conducted to test the effects of mobile texting and gaming on gait with obstructions under different illumination levels. Design: Cross-sectional study. Methods: Twelve healthy adults aged 20 to 36 years (mean 23.5 years) were tested under six different conditions. All participants used touchscreen smartphones. Testing conditions included: 1) Walking with an obstruction under a bright illumination level; 2) walking with an obstruction with a low level of illumination; 3) walking with an obstruction while texting under a bright illumination level; 4) walking with an obstruction while texting with a low level of illumination; 5) walking with an obstruction while gaming under a bright illumination level; and 6) walking with an obstruction while gaming with a low level of illumination. All participants were asked to text the Korean national anthem by their own phone and play Temple Run 2 using an iPhone 5. Gait variances were measured over a distance of 3 m, and the mean value after three trials was used. A gait analyzer was used to measure the data. Results: Compared to normal gait with obstruction, gait speed, step length, stride length, step time, stride time, cadence while texting and gaming showed significant differences (p<0.05). Differences between the illumination levels included gait speed, step length, stride length, and step time (p<0.05) with no significant differences in stride time and cadence. Conclusions: Dual-tasking using a smartphone under low levels of illumination lowers the quality of gait with obstructions.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.156-168
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• 2017

Personal mobility (PM) can increase the mobility of individual, so that the elderly can be set as the target group for using PM because of relatively low walking ability to normal. In this study, we design PM device for elderly that can be used safely in the walking environment such as sidewalk. There are various obstacles in the walking environment, so the device must have mechanical performance to overcome all of them. In this study, we survey the status and level of obstacle factors in walking environment to determine the dynamic performance of the PM device for elderly. We check up several guidelines about walking facilities to define obstacle points for the device, establish field survey methodologies, and conduct field survey for some specific road sections. Based on the survey results, we confirm the possible problems that could arise when the dynamic performance of the device is selected based on the facility-related criteria. We also define the performance requirements for the device based on the requirements for electric wheelchair.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.1
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• pp.47-57
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• 2016

In this paper, we measured human body signals in order to verify a active harness system that we developed for gait and balance training. The experimental procedure was validated by tests with 20 healthy male subjects. They conducted motions of Activities of Daily Living(ADL)(Normal Walking, Stand-to-Sit, Sit-to-Stand, Stair Walking Up, and Stair Walking Down) according to body weight support rates (0%, 30%, 50% of subjects' body weight). The effectiveness of the active harness system is verified by using the results of foot pressure distribution. In normal walking, the decrease of fore-foot pressure, lateral soleus muscle and biceps femoris muscle were remarkable. The result of stand-to-sit results motion indicated that the rear-foot pressure and tibialis anterior muscle activities exceptionally decreased according to body weight support. The stair walking down show the marked drop of fore-foot pressure and rectus femoris muscle activities. The sit-to-stand and stair walking up activities were inadequate about the effect of body weight support because the velocity of body weight support system was slower than male's activity.

• Journal of the Korean Home Economics Association
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• v.45 no.10
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• pp.1-11
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• 2007

This study was performed to identify the nutritional status and eating behaviors of underweight adolescent females aged 15 to 19 years. The subjects were selected using data from 2001 NHANS of Korea, and included 28 underweight and 160 normal-weight subjects. We found that the underweight group had significantly lower weight (9.8 kg), waist (6.9 cm), and hip circumference (7.2 cm) values than the normal-weight group; however height and waist-hip ratio were not different. Serum indices were within normal ranges and showed no differences between the two groups. The energy and nutrient intakes of most of the subjects were considered poor. For intake levels, the proportion of subjects below the EAR, NAR and INQ of each nutrient were also not significantly different between the groups. There were no differences in frequency for skipping meals, snacking, and eating-out between the groups. When comparing food frequency data for 62 food items, the underweight group consumed significantly more often of eggs, dried anchovies, mackerel, shellfish, and mushrooms than the normal-weight group. The former also had significantly less excercise/walking, more diet-control, and more rest/sleep than the latter. Subjects in both of two groups perceived their body images as over weight, so they practiced diet-control to reduce body weight, which is considered harmful as a healthy weight. In conclusion, the underweight group showed no differences in items of biochemical indices, nutrient intakes, and many dietary behaviors, but subjects revealed significantly higher food intake frequencies for several protein foods, as well as less excercise/walking, and more rest/sleep than the normal-weight group.

• Journal of Korean Academy of Rural Health Nursing
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• v.7 no.2
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• pp.51-58
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• 2012

Purpose: to investigate the relationship of between socioeconomic characteristics, and weight perception and lifestyle on body mass index (BMI) in Korea. Method: Participants were 2,405 people recruited from the 2007 Fourth Korea National Health and Nutrition Examination Surveys. Data included weight perception, BMI, and lifestyle factors and was analyzed using ${\chi}$ 2-test, logistic regression Results: Perception of weight was significantly different according to gender, age, education and residence. In the obesity group 21.6% perceived their weight as normal whereas 29.6% of the normal group perceived their weight as obese. In the obesity group, men who were over 70 years old, rural residents and only had elementary education perceived their weight range as normal. In the normal weight group, women who were urban residents and university graduates more frequently perceived their weight as obese. Logistic regression analysis of lifestyle factors, indicated that misperceived obesity was associated with walking (OR=0.703, 95% CI=0.553-0.896), weight control (OR=2.693, 95% CI=2.080-3.485), and health exam (OR=0.730, 95% CI=0.567-0.940) whereas misperceived normal weight was associated with walking (OR=0.696, 95% CI=0.497-0.975), weight control (OR=0.523, 95% CI=0.363-0.749). Conclusion: Results indicate differences in self-perceived weight and life style and provide information that can be used for health promotion program development.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.705-706
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• 2007