• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.4
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• pp.23-29
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• 2002

Radar method can be effective in probing concrete structures damaged by earthquake. Data analysis is usually performed in time domain, by considering time delay of the wave due to the dielectric constant of concrete. In this study, improved data analysis has been performed using signal processing scheme of spectra analysis and filtering. Three antenna with 900MHz, 1㎓, and 1.5㎓ center frequency were used to detect a steel bar or delamination in specimens for obtaining data, Frequency spectrum was filtered in low pass, high pass, and band pass varying cutoff frequency with 1/3 octave in frequency domain. The most effective cutoff frequency for each frequency has been determined as the range for 2 octave lower to 1 octave higher and 2 octave lower to 1 octave lower. This result provided a basis in improving data analysis capability using frequency domain filtering.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.4
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• pp.808-814
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• 2007

In this paper, the measurement system of crane moving range is concerned with range recognition technology using phase and magnitude of radio wave. By the proposed technology, we design the radio transmitter and receiver and realize the measurement system, and save the data in disk that is earned from 900Mhz RF signal, middle frequency 450khz of analog signal. As a result of RF measurement, we got 9.3 dBm of RF output and 96 dBc@10khz of phase noise. Range information is earned the data through digital signal processing of IF signal. For the estimation of range measured, we analyze the difference between real range and measurement range, and also suggest the method to remove the measurement error using average processing and amplitude properties. A result is 0.12 and 0.00422 deviation in l0mn-30m and within 5m respectively, and then 2.4E-04 deviation in 4m by using compensation of level characteristics lately.

• Human Ecology Research
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• v.57 no.3
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• pp.341-352
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• 2019

This study examined the effect of maternal positive parenting attitudes on school adjustment among multi-cultural adolescents in Korea and investigated if multi-cultural adolescents' ego-resiliency mediates the relationship between maternal positive parenting attitudes and school adjustment. We used panel data from the fifth wave (2015) of the Multicultural Adolescents Panel Study (MAPS) collected by the National Youth Policy Institute. Participants were 1,297 multi-cultural adolescents (639 boys, 658 girls) who are second-year middle school students and have foreign mothers. SPSS 25.0 performed descriptive statistical analysis and correlation analysis. The structural equation model (SEM) was estimated with Mplus 5.12. The results of this study were as follows. First, a higher level of maternal positive parenting attitudes were related to higher level of ego-resiliency and school adjustment for multi-cultural adolescents. Second, maternal positive parenting attitudes had an indirect effect on school adjustment for multi-cultural adolescents via ego-resiliency. The results of this study indicate that maternal positive parenting behaviors would help improve the school adjustment of multi-cultural adolescents by increasing the level of ego-resiliency. In addition, the results of this study suggest that improving ego-resiliency for multi-cultural adolescents can be an effective method to help in school adjustment, as well as education for maternal parenting attitude.

• Fashion & Textile Research Journal
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• v.21 no.2
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• pp.179-188
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• 2019

Domestic apparel products labeled as 'Made in Korea' in the Chinese market are recognized as a high quality products due to the influence of the Korean Wave (Intergen Consulting Group, 2007). This study analyzes the patterns and order arrangement types of a fashion brand company commissioned to produce apparel in Seoul, Korea in order to rebuild a network of small sewing factories scattered in Korea, reorganize operations, and to find the possibility of regenerating the Korean sewing industry by establishing contact points with domestic sewing factories. We surveyed 100 apparel brand companies in Seoul listed in the 2014/2015 Korea Fashion Brand Annual (Apparel News, 2014) and conducted a questionnaire survey on the company's general management status, type of fabric materials dealt with, and major contact points and methods of production handling. The frequency analysis indicated that the main production material with cloth type was woven fabric with ladies' clothes. The Planning MD team has the highest rate of ordering production with delivery method to the production factory after purchasing fabric and trims. Most respondents answered that they would select a production factory based on recommendations from acquaintances. This was due to a lack of no objective indicator provided by the sewing factory at present and the absence of objectively proceeded communication with brand companies. In this study, we analyze various conditions and measurements for production arrangements from a fashion brand company to revitalize sewing factories in Korea.

• Korean Journal of Applied Biomechanics
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• v.29 no.2
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• pp.105-112
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• 2019

Objective: The main purpose of this study was to investigate the effects of wearing an ankle weight belt while performing gait in water by focusing on the effect of using ankle weights have on the gait kinematics and the muscle activities for developing optimum training strategies. Method: A total of 10 healthy male university students were recruited for the study. Each participant was instructed to perform 3 gait conditions; normal walking over ground, walking in water chest height, and walking in water chest height while using ankle weights. All walking conditions were set at control speed of $4km/h{\pm}0.05km/h$. The depth of the swimming pool was at 1.3 m, approximately chest height. The motion capture data was recorded using 6 digital cameras and the EMG was recorded using waterproof Mini Wave. From the motion capture data, the following variables were calculated for analysis; double and single support phase (s), swing phase (s), step length (%height), step rate (m/s), ankle, knee, and hip joint angles ($^{\circ}$). From the electromyography the %RVC of the lower limb muscles medial gastrocnemius, rectus femoris, erector spinae, semitendinosus, tibialis anterior, vastus lateralis oblique was calculated. Results: The results show significant differences between the gait time, and step length between the right and left leg. Additionally, the joint angular velocities and gait velocity were significantly affected by the water resistance. As expected, the use of the ankle weights increased all of the lower leg maximum muscle activities except for the lower back muscle. Conclusion: In conclusion, the ankle weights can be shown to stimulate more muscle activity during walking in chest height water and therefore, may be useful for rehabilitation purposes.

• Journal of the Korea Fashion and Costume Design Association
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• v.21 no.3
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• pp.137-147
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• 2019

The purpose of this study, I investigate the new trend, 'new-tro', through the music video costumes of young generations, and analyze the meaning and characteristics of 'new-tro'. The research method is, select 30 music video with new-tro fashion style on the music sites, and the fashion styles were analyzed in 11 music videos checked and selected by 100 students. As a definition of the term, 'retro' refers to a phenomenon in which the past reappears in modern time, and 'new-tro' is a new retro trend, a social phenomenon that enjoys the old with a modern sense, and is a compound word of 'new' and 'retro'. 'new-tro' is a modern reinterpretation and rebirth of the past style, and 'fu-tro' is a style of coexistence between the past and the future. In the music video, fashion is a media language and cultural code, and it creates trend or new fashion, that communicates with the public, stimulating emotions. As a result of the research, the common trend phenomenon expressed in the music video costume of 'new-tro' trend which appeared in 2000s is as follows. 1. New-tro style starts with items that were famous in the past. 2. It is one of postmodern marketing using color, print and logo. 3. It spreads quickly by the influence of culture that is characteristic of the Internet and SNS world. 4. It is bottom up propagation phenomenon of street fashion. 5. It is a time game where modern people connect the past with the present. 6. "new-tro" continues to evolve for that time, based on 'retro'. New-tro, an evolutionary version of the 21st century retro wave. and it is a key to marketing effectiveness as a sympathetic elements of 1020 generations with the reproduction of memories.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.4
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• pp.305-316
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• 2022

Numerous research revealed a strong association between the ionospheric perturbations and various natural hazards. The ionospheric measurements from Global Navigation Satellite System (GNSS) observations provide the state of electron contents in the ionosphere that contributes to investigate the source events. In this study, two geophysical events occurred on 23 January 2018, the 7.9 Mw earthquake in Alaska and Kusatsu-Shiranesan volcanic eruption in Japan, are examined to characterize the fingerprint of each event in the ionosphere. Firstly, we extracted the Total Electron Content (TEC) from GNSS measurements, then isolated disturbed wave signatures from the TEC measurements that is referred to as a traveling ionospheric disturbance (TID). As TIDs are short-term ionospheric variations, the major trend of GNSS TEC measurements should be properly removed. We applied a natural neighbor interpolation method together with a leave-one-out cross validation technique for detrending. After detrending the TEC, the remaining signals are further enhanced by applying a band-pass filter and TIDs are detected from them. Finally, the detected TIDs are verified as the response of the ionosphere to Kusatsu-Shiranesan volcanic eruption and Gulf of Alaska earthquake which propagated through the ionosphere with an average velocity of 530 m/s and 724 m/s, respectively. In addition, a coherence analysis is conducted to discriminate between the signatures from a volcanic explosion and an earthquake. The analysis reveals the TID waveforms from each single event are highly correlated, while a low correlation is found between the TIDs from the earthquake and explosion. This study supports the claim that different geophysical events induce the distinctive characteristics of TIDs that are detectable by the ionospheric measurements of GNSS.

• Current Optics and Photonics
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• v.6 no.6
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• pp.550-564
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• 2022

Optical microscopy is a useful tool for study in the biological sciences. With an optical microscope, we can observe the micro world of life such as tissues, cells, and proteins. A fluorescent dye or a fluorescent protein provides an opportunity to mark a specific target in the crowd of biological samples, so that an image of a specific target can be observed by an optical microscope. The optical microscope, however, is constrained in resolution due to diffraction limit. Super-resolution microscopy made a breakthrough with this diffraction limit. Using a super-resolution microscope, many biomolecules are observed beyond the diffraction limit in cells. In the case of volumetric imaging, the super-resolution techniques are only applied to a limited area due to long imaging time, multiple scattering of photons, and sample-induced aberration in deep tissue. In this article, we review recent advances in super-resolution microscopy for volumetric imaging. The super-resolution techniques have been integrated with various modalities, such as a line-scan confocal microscope, a spinning disk confocal microscope, a light sheet microscope, and point spread function engineering. Super-resolution microscopy combined with adaptive optics by compensating for wave distortions is a promising method for deep tissue imaging and biomedical applications.

• Journal of the Earthquake Engineering Society of Korea
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• v.26 no.1
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• pp.13-22
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• 2022

This study proposes a low-cycle fatigue life derived from measurement points on pipe elbows, which are components that are vulnerable to seismic load in the interface piping systems of nuclear power plants that use seismic isolation systems. In order to quantitatively define limit states regarding leakage, i.e., actual failure caused by low-cycle fatigue, in-plane cyclic loading tests were performed using a sine wave of constant amplitude. The test specimens consisted of SCH40 6-inch carbon steel pipe elbows and straight pipes, and an image processing method was used to measure the nonlinear behavior of the test specimens. The leakage lines caused by low-cycle fatigue and the low-cycle fatigue curves were compared and analyzed using the relationship between the relative deformation angles, which were measured based on each of the measurement points on the straight pipe, and the moment, which was measured at the center of the pipe elbow. Damage indices based on the combination of ductility and dissipation energy at each measurement point were used to quantitatively express the time at which leakage occurs due to through-wall cracking in the pipe elbow.

• Journal of the Korean Geotechnical Society
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• v.38 no.11
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• pp.31-42
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• 2022

This study verified numerical analysis of the liquefaction phenomenon using LEAP-2017 international round-robin centrifuge test results. Dynamic centrifuge test is performed by applying a 1 Hz tapered sine wave to the model soil deposit, which was formed under a water table in a surface slope of 5° using Ottawa F-65 sand. A numerical model was made on a prototype scale and analyzed using the finite difference method in 2D and 3D conditions. The analyses were verified for acceleration and pore-water pressure histories with depth and residual displacement. Verification results revealed that all numerical liquefaction models agree reasonably with the test result for acceleration histories but not for pre-water pressure histories. Numerical analyses showed much smaller residual displacement than the centrifuge test. Thus, it is necessary to compare the results of numerical analysis with the centrifuge test performed by other institutes in the future.