• Earthquakes and Structures
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• v.18 no.6
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• pp.677-689
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• 2020

A building structural system of moment resisting frame (MRF) with concrete filled steel tubular (CFST) columns and wide flange H beams, is one of the most conveniently constructed structural systems. However, there were few studies on evaluating seismic performance of full-scale CFST columns under high axial compression. In addition, some existing famous design codes propose various limits of width-to-thickness ratio (B/t) for steel tubes of the ductile CFST composite members. This study was intended to investigate the seismic behavior of CFST columns under high axial load compression. Four full-scale square CFST column specimens with a B/t of 42 were carried out that were subjected to horizontal cyclic-reversal loads combined with constantly light, medium and high axial loads and with a linearly varied axial load, respectively. Test results revealed that shear strength and deformation capacity of the columns significantly decreased when the axial compression exceeded 0.35 times the nominal compression strength of a CFST column, P₀. It was obvious that the higher the axial compression, the lower both the shear strength and deformation capacities were, and the earlier and faster the shear strength degradation occurred. It was found as well that higher axial compressions resulted in larger initial lateral stiffness and faster degradation of post-yield lateral stiffness. Meanwhile, the lower axial compressions led to better energy dissipation capacities with larger cumulative energy. Moreover, the study implied that under axial compressions greater than 0.35P₀, the CFST column specimens with B/t limits recommended by AISC 360 (2016), ACI 318 (2014), AIJ (2008) and EC4 (2004) codes do not provide ultimate interstory drift ratio of more than 3% radian, and only the limit in ACI 318 (2014) code satisfies this requirement when axial compression does not exceed 0.35P₀.

• Journal of Digital Convergence
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• v.17 no.11
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• pp.289-295
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• 2019

This study was conducted to present effective CPR by identifying the usefulness of Pad Attachment Glove. The study subjects and data collection were conducted from 1 April 2019 to 30 April on Paramedic students of G university located in G-wide city and analyzed using the SPSS/Win 23.0. The study found that the chest compressions after wearing pad attachment gloves were higher in the areas of Chest Compressions total score, Number of chest compressions, chest recoil rate, hand position accuracy, CPR velocity than before wearing them. It was understood that pad attachment gloves improved the quality of chest compressions more than Hands-Only CPR. This will be used as a basic material for cardiopulmonary resuscitation education in the future, and is believed to contribute to devising a practical program.

• Journal of the Korea Society of Computer and Information
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• v.25 no.3
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• pp.169-176
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• 2020

This study suggested a method to increase the quality of chest compressions in patients with cardiac arrest during transport. When providing cardiopulmonary resuscitation to a cardiac arrest patient in the pre-hospital phase, the quality of chest compressions should be improved by using a three-point fixed belt to the ambulance. Because the quality of the chest compression was increased when the 119 paramedic wears a 3-point fixed belt in addition to the chest compression method. Also, paramedics are less likely to be at risk. Therefore, if a 3-point fixed belt is worn in an ambulance during transport, 119 paramedics will be able to secure safety and provide high-quality chest compressions to cardiac arrest patients.

• The Korean Journal of Emergency Medical Services
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• v.24 no.2
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• pp.39-50
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• 2020

Purpose: This study aimed to compare the effect of chest compression and the resulting ventilation volume in walking cardiopulmonary resuscitation (CPR), straddling CPR, and mechanical CPR while moving manikins to main stretchers. Methods: We compared the chest compressions in terms of compression depth, number of incomplete releases, complete release depth, compression rate, duration between peak time of previous compression and peak time of current compression, and respiration. We analyzed the compression comparatively with the ventilation volume in three different types of CPR. Results: The chest compression depth was significantly improved during straddling CPR as compared to walking CPR, during which women were unable to achieve sufficient chest compression depth. A constant chest compression depth was maintained during mechanical CPR. Conclusion: High-quality chest compressions were difficult to achieve in moving spaces. Further, walking CPR may be helpful in men, but straddling or applying automatic chest compressions in women would result in more effective CPR. Our findings demonstrate the limitations and trends in administering CPR in men and women, which may be useful in devising better education and training methods in the future.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.2
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• pp.444-450
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• 1998

In the present investigation, it is attempted to derive a yield function and associated flow rules of loose metal powders to predict plastic deformation and density change during compaction. The loose metal powders yield by shear stress as well as hydrostatic stress and the yield strength is much smaller in tension than compression. Therefore, a yield function for the powders is expressed as a shifted ellipse toward the negative direction in the hydrostatic stress axis in the space defined by the two stresses. Each of parameters A, B and .delta. used in the yield function is expressed as a function of relative density and it is determined by uniaxial strain and hydrostatic compressions using Cu powder. Flow rules obtained by imposing the normality rule to the yield function are applied to the analyses of unidirectional, bidirectional and hydrostatic compressions, resulting in an excellent agreement with experiments. The yield function is further examined by checking volume changes in plane stain, uniaxial strain and shear deformations.

• Journal of the Ergonomics Society of Korea
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• v.11 no.2
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• pp.3-13
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• 1992

Resultant compressions on the L5/S1 joint of six subjects were studied as they lif- ted light weights in sitting and standing work postures. The subjects activities were photographed and analysed later by a static biomechamical computer model. Statistically significant differences were found between the result of the two postures analyses. Sitting posture showed significantly high compressions on the joint when doing several material handling tasks having the same work loads from the hip joint. Therefore, it is recommended that working with light weights in standing is less hazardous than doint the same work sitting postures, although both the maximum compression forces are under the Action Limit suggested by NIOSH.

• Journal of the Korean Society of School Health
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• v.27 no.3
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• pp.130-139
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• 2014

Purpose: The object of this study was to compare the educational effect about self-efficacy and the quality of chest compressions of Hands-only CPR and Basic CPR. Methods: It's a nonequivalent control group pre-post repeated quasi-experiment study conducted with entire fifth grade students belong to one school in H city. The study participants are 68 persons, and data were collected from December 2, 2013 to February 7, 2014. Self-efficacy was measured by 10 items, and the quality of chest compressions was measured by 5 variables which are average compression depth(mm), average rate (n/min), average count per minutes (n), abnormal placement (n), compression accuracy (%). Results: Self-efficacy of the experimental group and control group showed no significant difference but showed significant difference over time and was the highest at posttest 1 (immediately after education), the lowest at pretest (before education), middle at posttest 2 (8weeks after education) (p<.001). Experimental group was significantly higher than control group in average rate per minute. At posttest 1, experimental group was $130.0{\pm}9.38$ times, control group was $95.1{\pm}11.82$ times. At posttest2, experimental group was $124.0{\pm}14.89$ times, control group was $90.8{\pm}14.89$ times.(p<.001). Average rate (n/min) was significantly declined at control group in the quality of chest compressions over time (t=-2.400, p=.022). Average count per minute and compression accuracy were declined significantly so it were not maintained to posttest2. Conclusion: We need continuous CPR education because self-efficacy of CPR getting lower significantly over time. Hands-only CPR can't be seen as a way to increase the CPR ability of elementary school students having difficulty to perform artificial breathing. And, because the effect of education is not maintained 8wks after training, the technique centered repeated training is needed and a method which can increase compression accuracy is also needed.

• Journal of Digital Convergence
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• v.17 no.7
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• pp.207-214
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• 2019

This study was designed to find effective CPR education methods by comparing and analyzing the quality of Field-Focus Type (FFT) CPR using SimPad and the quality of Video Self-lnstruction(VSI) CPR for the learners. The data collection were conducted from November 28, 2018 to December 5, 2018, on 64 first graders who completed CPR lectures at universities located in G metropolitan city, and analyzed using the SPSS ver. 23.0. The results of the study, Field Focus Type (FFT) CPR showed higher quality of Video Self-lnstruction (VSI) CPR in areas such as CPR total score, chest compressions score, chest compressions dept, chest compressions rate, chest compression velocity, total ventilation score, and Total number of ventilation than that of the subjects. Therefore, using Field Focus Type CPR (FFT) education law was found to improve the quality of cardiopulmonary resuscitation compared to the existing Video Self-lnstruction CPR (VSI) education method, and it is believed that it can be used as a basic data for cardiopulmonary resuscitation education in the future.

• The Korean Journal of Emergency Medical Services
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• v.24 no.3
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• pp.107-116
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• 2020

Purpose: We compared three chest compression methods to find an efficient method for performing infant cardiopulmonary resuscitation (CPR) for single rescuers and improving chest compressions quality. Methods: Thirty new marine police trainees at the Korea Coast Guard Education Institute were tested for five sessions using three methods of single rescuer infant CPR: two-finger chest compression, two-thumb encircling chest compression, and two-finger support chest compression. Results: The depth, accuracy, and number of compressions per minute of resuscitation were analyzed for the above three methods. The depth of two-finger chest compression, two-thumb encircling chest compression, and two-finger support chest compression was 3.53±0.20cm, 4.10±0.13cm, and 4.22±0.15cm, respectively. Accuracy was 23.86±12.59%, 54.11±10.8%, 71.55±18.81%, respectively, while the time for one cycle of 30 chest compression was 16.01±10.5 seconds, 16.45±0.85 seconds, and 16.56±0.91 seconds, respectively. Chest compression interruptions were 6.59±0.78 seconds, 7.17±0.37 seconds, and 6.97±0.35 seconds, respectively. The interruptions were consistent with the range of 5-10 seconds suggested by the American Heart Association. Conclusion: When one rescuer performs CPR for an infant in cardiac arrest, a comparative analysis of three methods showed that two-thumb encircling chest compression is the best for accuracy and efficiency of chest compressions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1392-1398
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• 2022

This study was conducted for effective CPR by comparing the quality of chest compressions when using a new chest compression method during pediatric CPR. As an experimental study by Randomized Crossover Design, the depth, speed, compression-to-relaxation ratio, ease, and stability were measured when performing chest compressions for 28 Emergency Medical Technicians who completed the BLS Health Care-Provider qualification. The collected data were analyzed by using the SPSS Ver. 23.0 for Win statistical program. To summarize the results of this study, if the new chest compression method was used for chest compression in pediatric CPR, the qualitative indicators of chest compressions were improved. It is good to stick to the existing method, but through the new chest compression method, it will be necessary to confirm the possibility of clinical use based on additional research on various age groups and environmental factors.