• Korean Journal of Applied Biomechanics
• /
• v.25 no.1
• /
• pp.85-94
• /
• 2015

Purpose : The purpose of this study was to investigate the influence on the ground reaction force parameters according to wearing positions of backpack for during stair ascending and descending. Methods : Participants selected as subject were consisted of young female(n=10) and performed stairs walks(ascending and descending) with 2 types of wearing position(front of trunk[FT], rear of trunk[RT]). Passive(Fz 1) and active(Fz 2) forces of the vertical GRF were determined from time function and frequency domain. Also shear forces(Fx, Fy 1, Fy 2), dynamic postural stability index(MLSI, APSI, VSI, DPSI), loading rate and center of pressure (${\Delta}COPx$, ${\Delta}COPy$, COP area) were calculated from time function and frequency domain. Results : Fx, Fy 1, Fy 2, and Fz 1 in GRF didn't show significant differences statistically according to the wearing positions of backpack(p>.05), but stair descending showed higher forces than that of stair ascending. Particularly, Fz 2 of stair ascending showed higher forces than that of stair descending(p<.001), RT types showed higher than that of FT types(p<.05). MLSI, APSI, VSI, and DPSI of stair descending showed the increased stability index than that of stair ascending(p<.05), MLSI of RT types showed the decreased stability index than that of FT types(p<.05). Loading rate didn't show significant differences statistically according to the wearing positions of backpack(p>.05), but stair descending showed higher loading rate than that of stair ascending(p<.001). Also, ${\Delta}COPx$ in stair descending showed the increased movement than that of stair ascending(p<.05). Conclusions : A backpack of 10 kg(10 kg(ratio of body weights $17.61{\pm}1.17%$) showed significantly change GRF parameters according to wearing positions during stair ascending and descending. If possible, we suggest that the dynamic stability, in case of stairs walking with a smaller weights can be further improved.

• Physical Therapy Rehabilitation Science
• /
• v.7 no.3
• /
• pp.134-138
• /
• 2018

Objective: The aim of this research was to investigate the effects of functional electrical stimulation (FES) applied to the gluteus medius (Gm) and tibialis anterior (TA) during stair climbing in persons with stroke compared to FES applied to the TA only during stair climbing, and during stair climbing without FES in persons with stroke. Design: Cross-sectional study. Methods: Twenty subjects with stroke participated in this study. Subjects were included if: 1) they were diagnosed as stroke at least 6 months before; 2) had Mini Mental State Examination- Korean score of 24 or higher; 3) were able to climb a flight of 10 stairs independently (with or without walking aid). The patients walked 10 stairs 3 times with FES applied to the Gm and TA, only TA, or no FES. There was a 1-minute rest period between each bout. The assessments were made using the Timed Up & Down Test and the Wii Balance Board. Results: Stair climbing with FES applied to the Gm and TA was significantly faster than stair climbing with FES applied to the TA only and without FES (p<0.05). Stair climbing with FES applied to the Gm and TA exhibited significantly greater sway velocity than stair climbing without FES (p<0.05). However, maximal sway distances were not significantly different between groups. Conclusions: Stair climbing with FES applied to the Gm and TA can be an important component of a rehabilitation program for improving stair climbing ability in persons with stroke.

• Journal of environmental and Sanitary engineering
• /
• v.3 no.2 s.5
• /
• pp.43-60
• /
• 1988

This study was carried out to determine traffic noise level and analyze noise reduction effects of various sound protection facilities in the area of Seoul, Inch'on, Songchoo and Seoul- Busan Expressway from March to Octover, 1987. The results were as follows; 1. As compared with the environmental standards and the traffic noise level in heavy noise areas, traffic noise levels observed were shown in higher than environmental standards. The noise levels in Seoul were determined at 12.8-18.2 dB(A) in daytime and 19.0-26.9 dB (A) in nighttime. And incase of inch'on, it were 6.7-9.6 dB(A) in daytime, 7.9-18.9 dB(A) in nighttime, respectively. 2. The environmental noise level observed in the backside of protection facilities, such as apartment, soundproof barrier and houses, which were constructed in paralled to the road was lower about 3-5 dB(A) than perpendicular to theroad. Noise recuction effect of upper stairs in apartment was higher than lower stairs. 3. The predicted noise level obtained from the equation $({\triangle}L\;=\; -10\;log\;(^{I'1}/Ii)\;was\;\pm\;1dB$ (A) and the correlation coefficient (r) was 0.923. 4. The noise reduction effect in backside of apartment was measured at on sites and predicted by total noise loss equation. The predicted noise level was 60.9 dB(A) and the measured level was 60.6 dB(A), respectively. 5. The narrow width landscape less than 10m width was almost no effect for the protection of traffic noise. According to the synthesis of the above results, the noise level of the road was exceeding mostly the environmental standard in the heavy traffic areas. The counterplan should be set as well. The insulation of noise protection facilities were effective by the location with near distance from the road edge. The reduction effect of double window in apartment was represented so much. The prediction model could be applied to estimate the noise levels in the roadside as well as the effectiveness for the noise protection facilities.

• Journal of Navigation and Port Research
• /
• v.37 no.3
• /
• pp.239-244
• /
• 2013

To increase the safety of onboard evacuation of guests who is unfamiliar with onboard living conditions, this study measured and compared the onboard walking speeds of 81 participants on a passenger ship, I t were found that the walking speeds at corridor on navigation were slower than those at berth by 27.2%, and the speeds of walking on the corner on navigation were slower than those at berth by 23.2%. This means that the ship motion on navigation directly influenced walking speeds. The walking speeds of upward-stairs and downward-stairs were measured to be 0.71m/s and 0.75m/s, respectively. From the crowd counter-flow experiments, because of the narrow space between participants, the walking speeds were decreased as person after person. And it was clear that the group's walking speeds were determined by the walking speeds of leading person(s) of the group. The walking speeds obtained this study were different from those of IMO guideline(MSC/Circ 1033).

• Korean Journal of Applied Biomechanics
• /
• v.16 no.4
• /
• pp.31-38
• /
• 2006

The purpose of this study was to investigate the effect of changing the steps height on the joint moment of lower extremity in stair-descent activity of elderly persons. Data were collected by 3-D cinematography and force platform. 9 male elderly subjects in the 60s and 70s participated in this study. All subjects performed a stair-descent in four different heights of stairs (10, 14, 18, 22cm) having 5 step staircase. The results were as follows. 1. For the step height of 22cm the maximum. plantarflexion moment was the smallest and the largest for the step height of 14cm. 2. There was not a statistical difference shown for the extension moment of the knee joint for the different height of steps. 3. There was not a statistical difference shown for the flexion moment of the hip joint for the varying height of steps but on average for the 18cm step this increased rapidly. 4. The smallest maximum. value for inversion moment was revealed for the step height of 10cm and this increased significantly for the step height of 22cm. 5. The smallest maximum. value for abduction moment of the hip joint was revealed for the step height of 10cm and this increased significantly for the step height of 22cm. 6. There was no significant difference shown for the maximum. abduction moment for the hip joint. The main conclusion is that there is a huge difference in the moment of the lower extremities for the elderly while walking down a stairs with a step height above 18 cm and that this moment increased or decreased rapidly under a condition of step height being 22cm. With the results from this research and related research of elderly walking upstairs it can be shown that the step height has a large role in the safety for the elderly.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.15 no.1
• /
• pp.59-64
• /
• 2005

In the paper, we propose an intelligent walking algorithm of biped robot on the uneven ground and a posture stabilization algorithm against external forces. At first, the mechanics and the control system of biped robot that can walk on the uneven ground and stand external forces are designed. We propose obstacle hurdling, incline walking. and going-up stairs algorithm by using infrared sensors and FSR sensors. Also, posture stabilization algorithm against external forces is designed using FSR sensors. Infrared sensors ate used to detect the obstacles in the working environment and FSR sensors are used to obtain the ZMP of biped robot. The developed biped robot can be controlled by the remote control system using vision system and RF module. The experimental results show that the biped robot Performs obstacle avoidance, obstacle hurdling, walking on the inclined plane, and going up stairs using the proposed walking and stabilization algorithm.

• Fire Science and Engineering
• /
• v.16 no.3
• /
• pp.48-55
• /
• 2002

This study presents a treatment of suitable flame retardant through evaluating fire performance after treating flame retardant of fibers for development of welding blanket. The experimental samples used were commercial fibers and we are treated fibers with the flame retardant liquid and the flame retardant paint. The fire performance of the sample was carried out according to the Korea and Japan Standard. As the results of the fire performance experiment, the treated fiber in samples had enough in the performance of flame and fire retardant and the grade of their was from grade A to grade C according to flame and fire retardant standard. The lower oxygen index indicated that all treated samples with the resist are satisfied with international standard. We con-sider that the welding blanket treated with grade A, B and C performance prevents fire spread regardless of the height of work stairs in the case of installation horizontally. Also, it is considered that the welding blanket treated with grade C performance prevents fire spread regardless of the height of work stairs in the case of installation vertically.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.19 no.4
• /
• pp.577-588
• /
• 2017

There are many constraints, both economically and ethically that experimenting human evacuation behavior in situations such as fire. Therefore, the evacuation behavior is simulated based on the existing studies. In recent years, the foundation has been established as computer performance advances, models closer to reality can be studied. In this study, the evacuation time in the subway platform was analyzed from modeling human behavior and smoke propagation in a fire. The evacuation efficiency was also examined by dividing the shape of the subway station platform by the stair position and comparing the evacuation times for each platform. As a result, it was found that the side platform was longer than the island platform by 36.82% more time to evacuation. The shape of the stairs is most advantageous in terms of evacuation form side type platform was 210 seconds and island type platform was 186 seconds, when a fire occurs in the center of the platform. And most favorable in location of evacuation stairs were located at 2/5 point and 4/5 from depending on the step location.

• Journal of the Korean Society of Costume
• /
• v.58 no.6
• /
• pp.124-144
• /
• 2008

This study is taken as the part of the cultural research on the Kaspian coastal region, which has a great significance as the start of human civilization and in the history of cultural exchange. This study is focused on the Achaemenid dynasty of the great Persian Empire that Iranians have established on the Parsa region, south of Iran on 6-4th century B.C. This research limits to the tribute-relief illustrated on the stairs of Apadana Palace in Persepolis during the age of Achaemenid dynasty. The objective of this research is classify and analyze Persians and its neighboring tribes, their dresses and the detailed elements of the dresses to complete the typology of the dresses in that period and use this to categorize the features of nomadic and agricultural tribes of costal areas of the Mediterranean Sea to Northern India and study the cultural exchange and its effects. Furthermore, we aim to use the above typology to revise the typology of the Korean traditional dresses that were formerly just sorted as a type of coat-trousers that classified as a nomadian Scythian dress type. The results of above analysis are as follows: The clothing of many tribes living in the coastal areas of Mediterranean Sea to the Northern India in the Achaemenid dynasty of Persia on 6th century B.C. shows that the typology of the dressings have close relationship with the region they live in. Such typology is displayed differently from tribes east and west of Iran. The tribes west of Iran showed characteristics of an agricultural tribe and the tribes east of Iran displayed features of a nomadic tribe. In addition, uniformed styles of dressing were displayed amongst many tribes sharing a common lineage. Such inference came from the fact that similar styles of dressings were identified not only in tribes east of Iran but also in tribes west of Iran.

• Korean Journal of Applied Biomechanics
• /
• v.26 no.3
• /
• pp.323-331
• /
• 2016

Objective: The aims of this study were 1) to develop easy-to-use rhythmic balance training equipment for the elderly and 2) to investigate the effect of training with the equipment on balance and physical function. Method: Twenty-one elderly individuals (age: $75.4{\pm}3.34yrs$, height: $152.07{\pm}4.81cm$, weight: $58.35{\pm}8.34kg$) participated in this study. Each participant underwent balance and physical function testing before and after 12 weeks of training with the equipment. Y-balance (i.e. dynamic balance) and one leg static balance tests were used for balance testing, and timed up- and-down-stairs and five times sit-to-stand tests were used for physical function testing. A paired t test was used to determine whether there was a significant pre- and post-training difference. Results: The rhythmic balance training equipment provided a fun and motivating training program with age-friendly music, dance movements for lower extremity strength training, and touch screen controls with simple features. Post-training left foot dynamic balance was significantly greater (p<.05), and static balance with eyes open was significantly improved (p<.05) compared to pre-training. Completion of the timed up-and-down-stairs and the five times sit-to-stand tests was significantly shorter (p<.05) compared to pre-training. Conclusion: Training using the equipment developed in this study improved balance and physical function in elderly participants.