• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.10 no.2
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• pp.57-72
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• 2004

Background : The part to be very important that we make the physical development rightly at elementary school student days. Objective : This study investigated the relation of a physical health status which itself recognizes and an exercise performance situation out for an elementary school students. Methods : This cross-sectional study examined health and exercise performance status of 1,032 elementary school children. To examine children's a physical injury experience and injury occurrence characteristic and a personal computer utility condition, a body alignment status of the student which parents recognize and the relation of a fatigue and concentration level was an investigation with other factors. Results: An average age of the children was the 10.95 yr and an average weight was the 39.02 kg and an average height was the 145.17cm. The student to be experiencing currently an pain occurrence was 192(19.07%). It was most high to the grade 6(23.33%) compared with different grade(p<.01). Physical pain occurrence rate did not exist by gender(p>.05). There is most an pain occurrence region the ankle(38.0%). They had a 27.19% an physical injury experience of the students. A injury rate was revealed that were high as were the high grade(grade 6, 36.72%)(p<.01). A reason of the injury rate was high in a collision at the body(19.84%), falling down(18.68%) sequence at a traffic accident(22.96%)(p<.05). There were the significant relation to the school year the reason of the injury (p<.05). Currently there was the student to be taking special exercises a 57.97%. This that they have the relation with exercise with physical pain students to recognize 23.8%. The significant relation did not exist in the physical exercise execution and pain occurrence on the body(p>.05).

• Safety and Health at Work
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• v.12 no.4
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• pp.511-516
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• 2021

Background: Difficulties in walking and balance are risk factors for falling. This study aimed to predict dynamic balance based on demographic information and anthropometric dimensions in construction workers. Methods: This descriptive-analytical study was conducted on 114 construction workers in 2020. First, the construction workers were asked to complete the demographic questionnaire determined in order to be included in the study. Then anthropometric dimensions were measured. The dynamic balance of participants was also assessed using the Y Balance test kit. Dynamic balance prediction was performed based on demographic information and anthropometric dimensions using multiple linear regression with SPSS software version 25. Results: The highest average normalized reach distances of YBT were in the anterior direction and were 92.23 ± 12.43% and 92.28 ± 9.26% for right and left foot, respectively. Both maximal and average normalized composite reach in the YBT in each leg were negatively correlated with leg length and navicular drop and positively correlated with the ratio of sitting height to leg length. In addition, multiple linear regressions showed that age, navicular drop, leg length, and foot surface could predict 23% of the variance in YBT average normalized composite reach of the right leg, and age, navicular drop, and leg length could predict 21% of that in the left leg among construction workers. Conclusion: Approximately one-fifth of the variability in the normalized composite reach of dynamic balance reach among construction workers using method YBT can be predicted by variables age, navicular drop, leg length, and foot surface.

• Journal of Trauma and Injury
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• v.34 no.3
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• pp.191-197
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• 2021

Renal injuries occur in more than 10% of patients who sustain blunt abdominal injuries. Non-operative management (NOM) is the established treatment strategy for lowgrade (I-III) renal injuries. However, despite some evidence that NOM can be successfully applied to high-grade (IV, V) renal injuries, it remains unclear whether NOM is appropriate in such cases. The authors report two cases of high-grade renal injuries that underwent NOM after embolization in a hybrid emergency room (ER) system with a 24/7 in-house interventional radiology (IR) team. A 29-year-old male visited Wonkwang University Hospital Regional Trauma Center complaining of right abdominal pain after being hit by a rope. Computed tomography (CT) was performed 16 minutes after arrival, and the CT scan indicated a grade V right renal injury. Arterial embolization was initiated within 31 minutes of presentation. A 56-year-old male was transferred to Wonkwang University Hospital Regional Trauma Center with a complaint of right flank pain. He had initially presented to a nearby hospital after falling from a 3-m height. Thanks to the key CT images sent from the previous hospital prior to the patient's arrival, angiography was performed within 8 minutes of the patient's arrival and arterial embolization was completed within 25 minutes. Both patients were treated successfully through NOM with angioembolization and preserved kidneys. Hematoma in the first patient and urinoma in the second patient resolved with percutaneous catheter drainage. The authors believe that the hybrid ER system with an in-house IR team could contribute to NOM and kidney preservation even in high-grade renal injuries.

• Fire Science and Engineering
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• v.32 no.6
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• pp.69-73
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• 2018

This study examined the reduction effect of a hydrodynamic force acting on the vertical wall of a portable water storage tank with a convex bottom floor. For the numerical simulation, the linearized Peregrine's equation was used to analyze the lapping waves in the tank caused by water falling from a supplying nozzle. The hydrodynamic force could be calculated by measuring the maximum run-up wave height at the vertical wall. The initial conditions of the numerical experiments were set up by controlling the positions and heights of the water supplying nozzle. Finally, the hydrodynamic force acting on the vertical wall can be reduced by the convex bottom design of the portable water storage tank so it can be applied to improve the structural stability.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.4
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• pp.78-87
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• 2021

Understanding the liquid propellant transport phenomena in low gravity is essential for developing Korea Space Launch Vehicle (KSLV) upper-stage for the diversity of space missions. A low-gravity environment can be simulated via the free-fall method on the ground; however, the air drag is inevitable. To reduce air resistance during free fall, air-drag shield is usually adopted. In this study, the free-fall method was performed with an air-drag shield from a 7-m height tower. The acceleration of a falling object was measured and analyzed. Low gravity below 0.01 g was achieved during 1.2-s free fall with the air-drag shield. The minimum gravitational acceleration value at 1.2-s after free fall was ±0.005 g, which is comparable to the value obtained from Bremen drop tower experiments, ±0.002 g. A prolonged free-fall duration may enhance the low-gravity quality during the drop tower experiments.

• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.2023-2030
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• 2022

A novel pulse fitting analysis (PFA) method is presented for the acquisition of nuclear spectra. The charging process of the feedback capacitor in the resistive feedback charge-sensitive preamplifier is equivalent to the impulsive pulse, and its impulse response function (IRF) can be obtained by non-linear fitting of the falling edge of the nuclear pulse. The integral of the IRF excluding the baseline represents the energy deposition of the particles in the detector. In addition, since the non-linear fitting process in PFA method is difficult to achieve in the conventional architecture of spectroscopy system, a new multi-channel analyzer (MCA) based on Zynq SoC is proposed, which transmits all the data of nuclear pulses from the programmable logic (PL) to the processing system (PS) by high-speed AXI-Stream in order to implement PFA method with precision. The linearity of new MCA has been tested. The spectrum of ¹³⁷Cs was obtained using LaBr₃(Ce) scintillator detector, and was compared with commercial MCA by ORTEC. The results of tests indicate that the MCA based on PFA method has the same performance as the commercial MCA based on pulse height analysis (PHA) method and excellent linearity for γ-rays with different energies, which infers that PFA method is an effective and promising method for the acquisition of spectra. Furthermore, it provides a new solution for nuclear pulse processing algorithms involving regression and iterative processes.

• Journal of the Korean Society of Radiology
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• v.82 no.6
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• pp.1594-1599
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• 2021

A 64-year-old male visited our emergency department due to severe right flank pain after falling from a 2-meter height. Contrast-enhanced CT revealed a right hemothorax with multiple fractures in the right ribs and iliac bone. A small hematoma in the right perihepatic space was noted, but there was no hepatic laceration on CT. Initial surgical management led to continuous uncontrolled bleeding around the porta hepatis, and subsequent arterial angiography could not demonstrate a bleeding focus. However, immediate follow-up CT showed contrast extravasation on the left side of abdomen, and a percutaneous transhepatic portal venogram revealed active bleeding from the left portal vein. Although the wound was embolized with a glue, the patient suffered from a cardiac arrest and finally expired. In conclusion, during evaluation of abdominal trauma patients, portal vein bleeding and contrecoup injuries should be considered when hepatic arteriography findings are unremarkable.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.2
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• pp.1-11
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• 2023

This study intended to develop a technique for quantitatively and 3-dimensionally predicting the potential failure zone and impulse that may occur when trees are fall down. The main outcomes of this study are as follows. First, this study established the potential failure zone and impulse calculation formula in order to quantitatively calculate the risks generated when trees are fallen down. When estimating the potential failure zone, the calculation was performed by magnifying the height of trees by 1.5 times, reflecting the likelihood of trees falling down and slipping. With regard to the slope of a tree, the range of 360° centered on the root collar was set in the case of trees that grow upright and the range of 180° from the inclined direction was set in the case of trees that grow inclined. The angular momentum was calculated by reflecting the rotational motion from the root collar when the trees fell down, and the impulse was calculated by converting it into the linear momentum. Second, the program to calculate a potential failure zone and impulse was developed using Rhino3D and Grasshopper. This study created the 3-dimensional models of the shapes for topography, buildings, and trees using the Rhino3D, thereby connecting them to Grasshopper to construct the spatial information. The algorithm was programmed using the calculation formula in the stage of risk calculation. This calculation considered the information on the trees' growth such as the height, inclination, and weight of trees and the surrounding environment including adjacent trees, damage targets, and analysis ranges. In the stage of risk inquiry, the calculation results were visualized into a three-dimensional model by summarizing them. For instance, the risk degrees were classified into various colors to efficiently determine the dangerous trees and dangerous areas.

• 한국체육학회지인문사회과학편
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• v.57 no.3
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• pp.345-356
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• 2018

Objective: The purpose of this study was to investigate the local stability of the lower extremity joints and muscle activation patterns of the lower extremity during walking between falling and non-falling group in the elderly women. Method: Forty women, heel strikers, were recruited for this study. Twenty subjects (age:72.55±5.42yrs; height:154.40±4.26cm; mass:57.40±6.21kg; preference walking speed:0.52±0.17m/s; fall frequency=1.70±1.26 times) had a history falls(fall group) within two years and Twenty subjects (71.90±2..90yrs; height:155.28±4.73cm; mass:56.70±5.241kg; preference walking speed: 0.56±0.13m/s) had no history falls(non-fall group). While they were walking on a instrumented treadmill at their preference speed for a long while, kinematic and EMG signals were obtained using 3-D motion capture and wireless EMG electrodes, respectively. Local stability of the ankle and knee joint were calculated using Lyapunov Exponent (LyE) and muscles activation and their co-contraction index were also quantified. Hypotheses were tested using one-way ANOVA and Mann-Whitey. Spearman rank was also used to determine the correlation coefficients between variables. Level of significance was set at p<.05. Results: Local stability in the knee joint adduction-abduction was significantly greater in fall group than non-fall group(p<.05). Activation of anterior tibials that acts on the foot segment dorsal flexion was greater in non-fall group than fall group(p<.05). CI between gastrocnemius and anterior tibials was found to be significantly different between two groups(p<.05). In addition, there was significant correlation between CI of the leg and LyE of the ankle joint flexion-extention in the fall group(p<.05). Conclusion: In conclusion, muscles that act on the knee joint abduction-adduction as well as gastrocnemius and anterior tibials that act on the ankle joint flexion-extention need to be strengthened to prevent from potential fall during walking.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.111-121
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• 2001

Rockfall protection fences are used for diminishing rockfall damage in roads side slopes. In order to install the fences in effective way, the conditions of rock slopes and total predicted impact energy of fa11ing rock should be considered. However, the fences have been constructed without any consideration for lithology, height and slope angle of rock slope in Korea. In addition, the information about the performance of the protection fences, which should be evaluated by in-situ test or laboratory test in order to check out the practical use in the field, is not available. Therefore, in design manual for the rockfall protection fence, the specific details for the installation of this type of fence are not provided yet. The full sized rockfall in situ test was carried out for the calculation of falling energy of rock and the evaluation of the maximum energy absorbing capacity of fence. For this test, the rock slopes whose heights are about 20 m and dip angle of 65 degree, have been chosen. This is because those geometries are mean height and slope angle of most road cut slopes along Korean national highway. Based on the preliminary simulation procedure, four different sizes of concrete ball (0.7, 1.3, 2.3 and 4.3 ton) were prepared and flour different types of protection fence were constructed. The results of this test provide information about the maximum energy absorbing capacity of the fence, kinetic energy of rockfall and restitution coefficient, and these results can be utilized in the establishment of rockfall fence design and construction manual.