• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.719-727
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• 2021

In the field of architecture, retractable devices capable of responding flexibly to the environment have been applied widely to large structures. Among these devices, the aesthetically pleasing retractable membrane is lightweight so that the membrane can be opened easily using only a traction device. On the other hand, because the towed membrane moves as it is connected to the main cable by a trolley, the number of trolleys needed increases in proportion to the roof's area. This study proposes an optimal model for an open-type trolley (OTT), which is used widely in these devices, using topology optimization. The analysis used the ANSYS program. A new model was proposed based on the results and reviewed through the feedback. Through this process, it was possible to develop a prototype with increased durability and reduced weight. For OTT, optimization was performed based on static analysis and the boundary conditions, so three prototypes were designed. A comparison of the proposed trolley with the conventional one under the same conditions revealed an up to 71.04% decrease in volume while the yield-strength reached 8.67 to 11.43%. In conclusion, the optimal trolley proposed was found to be reliable in terms of economy and stability.

• Journal of the Korean Geotechnical Society
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• v.37 no.5
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• pp.5-17
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• 2021

In this study, the shear behavior between pile-sandy soil interface was quantified based on series of rigorous ring shear test results. Ring shearing test was carried out to observe the shear behavior prior to failure and behavior at residual state between most commonly used pile materials - steel and concrete - and Jumunjin sand. The test was set to clarify the shear behavior under various confinement conditions and soil densities. The test results were converted in to representative friction angles for various test materials. Additional numerical analysis was executed to validate the accuracy of the test results. Based on the test results and the numerical validation, it was found that due to the dilative and contractive nature of sand, its interface behavior can be categorized in to two different types : soils with higher densities tend to show peak shear stress and moves on to residual state, while on the other hand, soils with lower densities tend to show bilinear load-transfer curves along the interface. However, the relative density and the confining stress was found to affect the friction angle only in the small train range, and converges as it progresses to large deformation. This study established a large deformation analysis method which can successfully simulate and predict the large deformation behavior such as ring shear tests. Moreover, the friction angle derived from the ring shear test result and verified by numerical analysis can be applied to numerical analysis and actual design of various pile foundations.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.119-125
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• 2020

Research on high-attenuation concrete for the vibration reduction performance by mixing epoxy-based synthetic resins and aggregates is actively being conducted. The curing time of high-attenuation concrete is very short because water is not used, and the physical and dynamic properties are very excellent. therefore, it is expected to be widely used in building structures requiring reduction of interior-floor noise and vibration. Furthermore, A way to expand the applicability of the high-damping concrete mixed with polymer in the field of reinforcement material have been variously studied. In order to replace polymer concrete with ordirnary concrete and existing anti-vibration reinforcement material, it is necessary to review overall vibration reduction performance considering physical properties, dynamic properties, productivity and field applicability. In this study, the physical and dynamic properties of polymer concrete by epoxy mixing ratio compared with ordirnary concrete. As a result, the elastic modulus was similar. On the other hand, polymer concrete for the compressive, tensile, and flexural strengths was quite more excellent. In particular, the measured tensile strength of polymer concrete was 4-10 times higher than that of ordirnary concrete. it was a big difference, and the frequency response function and damping ratio was studied through modal test and finite element analysis model. The dynamic stiffness of polymer concrete was 20% greater than that of ordirnary concrete, and the damping ratio of polymer concrete was approximately 3 times more than that of ordirnary concrete.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.553-560
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• 2022

This study was conducted to identify the factors affecting the quality of life of women over 10 years after menopause using data from 2014 to 2019 of the National Health and Nutrition Examination Survey. The subjects were 6,330. The data were analyzed by frequency analysis, t-test and multiple regression analysis using SPSS 25. As a result of the study, the factors affecting the health-related quality of life of women 10 years after menopause were age(F=30.625, p<.001), educational level(F=20.106, p<.001), perceived health status(F=187.925, p<.001, activity limitation(t=201.051, p<.001), arthritis(t=91.131, p<.001), osteoporosis(t=4.709, p=.030), hand grip strength(t=22.151, p<.001), perceived stress(F=32.775, p<.001), and depression(t=20.117, p<.001). The factors accounted for 35.1%(F=110.393, p<.001). In order to improve the quality of life of postmenopausal women, it is necessary to continuously evaluate and improve the factors affecting the quality of life from the early menopause.

• Maritime Security
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• v.3 no.1
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• pp.211-235
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• 2021

As a result of the Falkland Islands War from April 2 to June 14, 1982, Britain overcame severe economic depression and reclaimed the glory of the former British Empire by winning the war. On the other hand, Argentina was greatly affected by the collapse of a military dictatorship and the birth of a democratic government. This study suggests strategies for responding to maritime disputes that may occur in Dokdo Island in the future by applying "DIME on PMESII" to the Falkland Islands dispute. In particular, the study analyzes how DIME (diplomacy, information, military, and economy) capabilities have an effect as a means of the total national power of a country that effectively controls the disputed territory. Based on the results of this study, the response strategies related to the Dokdo maritime dispute are as follows. First, effective control over the disputed territory should be effectively maintained and strengthened like in Britain. This strategy inspires patriotism, supports the government during warfare, secures a just cause for war, and gains international support. Second, 'DIME on PMESII' was effective in modern warfare by focusing our DIME capabilities on the weaknesses of the other country's PMESII system. That is, wars are not won simply by the conflict of armed forces but by a nation's overall national strength, such as diplomatic, information, and economic capabilities. Third, appropriate strategies for neighboring countries are needed to overcome the possibility of limited warfare in the sea through preparations for Dokdo maritime disputes in the future.

• Tunnel and Underground Space
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• v.31 no.6
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• pp.469-479
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• 2021

As a material for preventing spalling of concrete, the effectiveness of PP fiber has already been confirmed. However, it is necessary to consider the maximum temperature that occurs during a fire, and to solve the mixing problem and the strength reduction problem that occur depending on the mixing amount. In this study, the fire resistance performance of tunnel segment linings according to the PP fiber content and air volume under the RABT fire scenario was investigated. As a result, no spalling or cross-sectional loss occurred in all test specimens, and when the PP fiber content was small, the maximum temperature was relatively high and the maximum temperature arrival time was also fast. On the other hand, no trend was found for the maximum temperature and arrival time according to the difference in air volume. In the internal temperature distribution results for the PP fiber mixing amount of 0.75, 1.0, 1.5, and 2.0 kg/m³, the results of 0.75 and 1.0 kg/m³ showed similar temperature distribution, and the results of 1.5 and 2.0 kg/m³ were similar. It was confirmed that the internal temperature distribution tends to decrease at the same depth when the amount of PP fiber mixed is large, and it was confirmed that a remarkable difference occurred from the results of 1.0 kg/m³ and 1.5 kg/m³ of PP fiber mixed amounts.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.81-88
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• 2021

Structural health monitoring (SHM) systems have attracted considerable interest owing to the frequent earthquakes over the last decade. Smart concrete is a technology that can analyze the state of structures based on their electro-mechanical behavior. On the other hand, most research on the self-sensing response of smart concrete generally investigated the electro-mechanical behavior of smart concrete under a static loading rate, even though the loading rate under an earthquake would be much faster than the static rate. Thus, this study evaluated the electro-mechanical behavior of smart ultra-high-performance concrete (S-UHPC) at three different loading rates (1, 4, and 8 mm/min) using a Universal Testing Machine (UTM). The stress-sensitive coefficient (SC) at the maximum compressive strength of S-UHPC was -0.140 %/MPa based on a loading rate of 1 mm/min but decreased by 42.8% and 72.7% as the loading rate was increased to 4 and 8 mm/min, respectively. Although the sensing capability of S-UHPC decreased with increased load speed due to the reduced deformation of conductive materials and increased microcrack, it was available for SHM systems for earthquake detection in structures.

• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.953-960
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• 2022

The measurement of branching ratio of ¹⁶⁷Yb radioactive isotopes from gamma-ray spectrum of ¹⁶⁹Tm(p,3n)¹⁶⁷Yb reaction were performed by using a 100-MeV proton linear accelerator of the Korea Multi-purpose Accelerator Complex (KOMAC). The ¹⁶⁷Yb isotope has a half-life of 17.5 minutes and decays to ¹⁶⁹Tm. The gamma rays generated from the ¹⁶⁷Yb isotope were measured using an HPGe detector gamma ray spectroscopy system. The energy calibration of the detector and the efficiency measurement of the detector were determined using a standard source. The gamma rays of known main energy (62.9, 106.2, 113.3, 143.5 and 176.3 keV) were measured. On the other hand, information about the intensity of the generated gamma rays is very inaccurate. Therefore, in this study, the decay strength of the main gamma rays was accurately measured. Overall, it was different from the previously known results, and in particular, it was found that the intensity of the main decay gamma ray, such as the 113.3 and 106.2 keV gamma ray, was overestimated, and it was found that the gamma ray, such as 62.9, 116.7 and 143.5 keV was underestimated. The present results are considered to be important information in the fields of nuclear fusion, astrophysics and nuclear physics in the future.

• Journal of Life Science
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• v.32 no.8
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• pp.611-621
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• 2022

Dimethyl sulfoxide (DMSO) is commonly used as control or vehicle solvent in preclinical research of neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) due to its ability to dissolve lipophilic compounds and cross the blood brain barrier. However, the biochemical effects of DMSO on the outcomes of preclinical research are often overlooked. In the present study, we investigated whether the long-term oral administration of 5% DMSO affects the neurological, functional, and histological disease phenotype of the copper/zinc superoxide dismutase glycine 93 to alanine mutation (SOD1-G93A) mouse model of amyotrophic lateral sclerosis. SOD1-G93A transgenic mice showed shortened survival time and reduced motor function. We found that administration with DMSO led to increased mean survival time, reduced neurological scores, and improved motor performance tested using the rotarod and grip strength tests. On the other hand, DMSO treatment did not attenuate motor neuron loss in the spinal cord and denervation of neuromuscular junctions in the skeletal muscle. These results suggest that DMSO administration could improve the quality of life of the SOD1-G93A mouse model of ALS without affecting motor neuron denervation. In conclusion, the use of DMSO as control or vehicle solvent in preclinical research may affect the behavioral outcomes in the SOD1-G93A mouse model. The effect of the vehicle should be thoroughly considered when interpreting therapeutic efficacy of candidate drugs in preclinical research.

• Korean Journal of Forensic Psychology
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• v.11 no.2
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• pp.173-190
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• 2020

The purpose of this study is to verify whether it is possible for participants to discriminate between innocent and guilty suspects when they are exposed to criminal information utilizing an autobiographical implicit association test (aIAT). A total of 49 college students were randomly assigned to guilty group, innocent-aware group, or innocent-unaware group. Participants performed an aIAT to detect suspects after performing either mock crime or control task. It was verified that innocent suspect and guilty suspect exposed with crime information could be distinguished through D-score and reaction time, converted to symbolize strength of the association between guilty sentences, innocent sentences, and truth sentences. As a result of the analysis, guilty group showed significantly higher D-score than both innocent-aware group and innocent-unaware group. guilty group also showed faster response time in true-guilty condition than true-innocent condition. This shows that the association of true-guilty conditions is stronger than that of true-innocent conditions. On the other hand, the innocent-aware group showed a faster response time in the true-innocent condition than the true-guilty condition, and innocent-unaware group showed no significant difference between the two conditions. Through this, it was confirmed that innocent suspects exposed to criminal information can be discriminated according to the aIAT pattern, which has a faster reaction rate to the truth and innocence union than the guilty group. This study confirmed that suspects exposed to criminal information can be effectively discriminated using aIAT, and further suggests the usefulness and potential of aIAT in the field of lie detection.