• Journal of Energy Engineering
• /
• v.29 no.3
• /
• pp.97-102
• /
• 2020

In this study, one-way fluid structure interaction analysis was adapted to verify the durability of the outdoor evacuation stair structure operated in the event of a fire when wind pressure caused by a typhoon was applied. To this end, flow analysis was performed with the flow field around the structure of the evacuation stair in a steady state, and the durability was analyzed through structural analysis such as structural stress, deformation, and fatigue life using these analysis results by fluid data input data for structural analysis. As a result of flow numerical analysis, the air flow was different according to the shape of the evacuation stair structure, and this flow velocity distribution generated by the total pressure on the structure surface. Through the structural analysis results calculated by this total pressure, the safety factor calculated as the maximum stress value was found to be more than the safety factor, and durability was proven by fatigue life and deformation analysis.

• Journal of the Korean Wood Science and Technology
• /
• v.29 no.1
• /
• pp.16-21
• /
• 2001

Improvement of sound absorption capability of wood and wood-based board by resonant absorption was attempted. Sound absorption coefficients of wood and wood-based board which contain normal, simple perforation and stair type perforation had been estimated by the tube method using standing wave ratio. Sound absorption coefficients of wood specimens of simply perforated and perforated with stair were higher than that of normal specimens. Especially, in case of stair type perforation, it was about 50 to 60% higher than that of normal specimen in the frequency of 3 to 4KHz. It was considered that the cavity which had been formed by perforation with stair type behaved as a single resonator. Wood-based board showed good sound absorption coefficients in the frequency from 125Hz to 2KHz and that of perforated board showed a little higher in the frequency from 300Hz to 500Hz than that of normal board. The computed data of resonant frequencies at several sizes of cavity showed good accordance with the estimated data of those.

• Journal of the Korea Safety Management & Science
• /
• v.18 no.1
• /
• pp.1-8
• /
• 2016

This study was conducted by survey and inspection of stair passage leading lights in shopping buildings which are more than 5 stories and have an underground parking lot located at Pyeongtaek-si and Seongnam-si. Number of shopping building for this study is 30 and of stair passage leading light inspected by two lights in each shopping building is 60. The result of this study is that the type of installed leading lights is LED(77%), and 60% of leading lights has problem such as no cleaning, scratch and discoloration, etc. The height of installed leading lights meets the fire law which is less than 1m from the floor. Visible condition of leading lights is good except some leading lights which have a little visible problem due to banner advertisement. 37% of standby power has flickered and went out. 93% of total leading lights meets the fire law which is more than 1lux from 0.5m distance, but cold cathode fluorescent lamps(CCFLs) have the problem which not meets proper brightness level based on fire law. In additional measurement result, zero lux of leading lights is 32%(from 1m distance), 68%(from 1.5m distance) and 98%(from 2m distance). Leading light is very important facility because it is eyes and guide when emergency. Therefore, proper fire facility operating function inspection and total detailed inspection are important to keep the good condition of leading light except simple visual check, and also improvement in law system of type approval, fire construction inspection and illumination level will be needed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.5
• /
• pp.2374-2381
• /
• 2012

The aims of this study are to verify the effecting factors in evacuation behavior under the corridor and stair width variation in evacuation experiments at university education facilities. To achieve these purposes, the present conditions of university education facilities were analyzed, and the evacuation experiment settings were established under different width of corridor and stairs. After the experiments, we asked the effecting variables to the evacuation behaviors under the variation of corridor, stair width and density of evacuee. The results of this study are as follows ; First, we found 3 main factors which affecting the evacuation behaviors ; environmental factors on building conditions, psychological factors on evacuee's characteristics and personal factors on evacuee's physical conditions. Second, the environmental factors such as the location of stairs for evacuation, recognition of wayfinding in fire condition are mainly affects the evacuation behaviors, but evacuee behaviors have little relations with fire extinguishing facilities and personality.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.10 no.1
• /
• pp.65-72
• /
• 2016

In this study, a fully active transfemoral prothesis with a knee joint is designed considering stair walking conditions. Since the torque at the knee joint required for stair walking condition is relative high compared with the one in normal walking condition, the proposed design has high torque generating mechanism. Moreover, the transfemoral prothesis is designed in compact size to reduce its weight, which is related to comfortable fit and fatigue of patients. Flat type BLDC motor is used for simple and compact structure and various components are used to generate required torque with target working angle and speed. The weight reduction of structure is carried out using optimization method after the initial design process is complete. The optimization is conducted under the load conditions of stair walking. The optimized design is validated via finite element analysis and experiments. As a result, the weight is reduced using topology and shape optimization but maintaining the safety of structure. Also the space efficiency is improved due to its compact size.

• Physical Therapy Rehabilitation Science
• /
• v.11 no.4
• /
• pp.478-487
• /
• 2022

Objective: This study was conducted to analyze the effect of wearable complex muscle support system on energy efficiency during walking in elderly. Design: Cross sectional study Methods: Twenty healthy elderly participated in this study. All subjects performed a 6 minuteswalk test(6MWT) and stair climbing test in dual, slack and no suit conditions. In each condition, oxygen consumption(VO₂), metabolic equivalents(METs), energy expenditure measures(EEm), physiological cost index(PCI), walking velocity and heartrate were measured. Through repeated measured ANOVA, it was investigated whether there was a statistically significant difference in the measurement results between the three conditions. Results: In over-ground walking, VO₂, METs and EEm showed significant differences between no suit and slack conditions(p<0.05). In stair climbing, VO₂ showed significant difference between slack and dual conditions(p<0.05). Also, METs and EEm showed significant differences between no suit and slack, and between slack and dual conditions(p<0.05). Conclusions: Wearing the wearable complex muscle support system for elderly does not have much benefit in energy metabolism efficiency in over-ground, but there is a benefit in stair walking.

• PNF and Movement
• /
• v.22 no.1
• /
• pp.31-41
• /
• 2024

Purpose: The purpose of this study is to compare lower extremity muscle activities and ankle joint angles between different foot strike patterns (forefoot strike, heelfoot strike) during stair ascent walking. Methods: The subjects of this study were 22 males who walked in each foot strike pattern on ascent stairs at a speed of 85 beats/min. During stair walking with the two types of foot strike patterns, the muscle activities of the rectus femoris, tibialis anterior, medial gastrocnemius, hamstring, and gluteus medius were measured. Additionally, ankle joint angles for inversion, eversion, dorsi flexion, and plantar flexion were recorded. Each participant underwent the experiment three times, with the foot strike pattern randomized. Results were averaged according to the foot strike pattern. Results: Significant differences in ankle angles were observed across all phases according to foot strike pattern. Muscle activities in the lower extremities showed significant differences in all phases except the swing 1 phase. Moreover, differences in foot movement trajectory were noted depending on the foot strike pattern. Conclusion: Walking on ascent stairs elicited differences in lower extremity muscle activities and ankle joint angles based on foot strike pattern. These findings can serve as foundational data for selecting a suitable foot strike pattern tailored to individual patient conditions when training patients in walking on ascent stairs.

• Physical Therapy Rehabilitation Science
• /
• v.13 no.2
• /
• pp.205-212
• /
• 2024

Objective: The purpose of this study is to confirm the exercise effect when combining wearable exercise assist robot, Bot fit's resist mode (Samsung Electronics) and stair climbing. Design: Cross-section study Methods: Targeting 53 adults and seniors, foot pressure and muscle activity were measured when climbing 3-story stairs using foot pressure measurement equipment (W-insole Science System) and surface muscle activity measurement equipment (sEMG; FreeEMG, BTS Bioengineering, Italy) using Bot Fit's resist mode. All subjects were measured without wearing Bot Fit, and the data between the two conditions were compared and analyzed. Results: The front area(p<0.01) and middle area(p<0.05) foot pressures of adults significantly increased when wearing the Bot fit. Frontal area foot pressure significantly increased in elderly people with knee arthritis and obesity(p<0.05). The gastrocnemius activity in all subjects significantly decreased after wearing Bot Fit(p<0.01). In elderly people with knee arthritis, the muscle activity of the rectus femoris was significantly reduced(p<0.05)., and in obese elderly people, the muscle activity of the gastrocnemius muscle was significantly reduced(p<0.05). Conclusions: Based on the results of this study, it is possible to induce correct stair climbing posture when climbing stairs using Bot fit resistance mode. In particular, it is expected to be an effective exercise for strengthening muscle endurance by increasing the activity of the rectus femoris muscle.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.10a
• /
• pp.301-306
• /
• 2009

High strength steels are widely used for lightweight automobile parts and the control of springback is very important in sheet metal forming. The object of this study is to develop the forming process for stair type side sill made of high strength steel, DP780. Stair type side sill with local formed area and geometry change area can improve stiffness and design freedom but there are a few studies for forming process. The forming technology considered in this paper is form type process, which have many advantages for farming of high strength steel compared with draw type process. Finite element analysis is carried out to predict formability and springback. It is shown that angle calibration of die is essential for reducing springback, and local forming involving bead is effective to control springback also. The effectiveness of local forming and angle calibration is verified by experimental.

• Korean Institute of Interior Design Journal
• /
• v.23 no.2
• /
• pp.193-200
• /
• 2014

This study aimed to evaluate how users are satisfied with village community center. It will develope and determine a most detailed design and requirements to maximizing for user's convenience. The study conducted interview survey using questionnaire based on universal design principles, to users of village centers that are in possible of cooperation of 25 village centers in Haw Soon district, Jeonnam province and used 160 cases to the analysis. The conclusion of this study is as follows. First, users showed most satisfaction about LDK space and dissatisfaction about design, stair/slope, entrance, and bathroom. Specially, users are dissatisfied with curtains at room and handralis at entrance. In terms of design, users about the indoor-outdoor environment as a whole was unsatisfactory. Second, survey on actual needs space scrutinized bathroom, kitchen, and stair/slope according to priority. In result of these surveys, user's satisfaction with village community center and actual needs space show needed improvements on bathroom and stair/slope space urgently.