• Journal of The Korean Society of Integrative Medicine
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• v.11 no.4
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• pp.177-188
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• 2023

Purpose : To identify trends in studies on the intersection of neurofeedback (NF) training and rehabilitation interventions for patients with stroke, as conducted over the past decade. Methods : This review included studies published from 2012 to 2022. A comprehensive database search was conducted using keywords such as "stroke", "electroencephalogram (EEG)", "brain wave", "nerve feedback", and "upper extremity function". Results : A total of 703 studies were initially retrieved. Of these, literature predating 2012, duplicate literature, non-experimental studies, and studies that did not target patients with stroke were excluded. After this screening, we retrieved the full texts of 15 articles and re-checked whether each study met the inclusion criteria of this study. The advisory members who participated in this study consisted of people with doctoral degrees and more than 5 years of clinical experience related to the rehabilitation of patients with stroke. Disagreements were resolved through discussions. Ultimately, 8 papers met the inclusion criteria and were included in the final analysis. Despite differences in the type and duration of NF training, the combination of NF training and rehabilitation intervention was found to be effective in promoting the functional recovery of the upper extremities, eliciting positive EEG changes, and inducing neurological changes in the brain. Conclusion : A meta-analysis involving a wider search range is needed in future studies. In addition, efforts are required to generalize the clinical application of these interventions. This can be achieved by supplementing the research methodologies through extensive review studies that encompass a diverse array of study designs.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.129-135
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• 2024

In this paper, an analytical approach for the design and analysis of an aperiodic electromagnetic bandgap (EBG)-based power distribution network (PDN) in high-speed integrated-circuit (IC) packages and printed circuit boards (PCBs) is proposed. Aperiodic EBG is an effective method to solve the noise problem of high-speed IC packages and PCBs. However, its analysis becomes challenging due to increased computation time. To overcome the problem, the proposed analytical method entails deriving impedance parameters for EBG island and the overall PDN, which includes locally placed EBG structures. To validate the proposed method, a test vehicle is fabricated, demonstrating good agreement with the measurements. Significantly, the proposed analytical method reduces computation time by 99.7 %compared to the full-wave simulation method.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.3
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• pp.311-318
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• 2024

In this paper, a design for a radio frequency(RF) and infrared(IR) absorber with metasurfaces is discussed in microwave frequency bands. The RF absorber includes double layers of metasurfaces to operate in S- and X-bands. Effects of sheet resistance of the metasurfaces and thicknesses of dielectric supporting layers on reflection responses are investigated. An IR stealth layer incorporates an array of conductive grids with slits to reflect IR signals but to transmit RF signals and visible rays. Periodicity of the grids and slits is studied for transmission responses in the X-band and a surface area ratio. Reflection responses of the RF/IR multispectral absorber are found to be lower than -10 dB and -16 dB in the S- and X-bands, respectively, from full-wave simulation. Finally, the RF/IR multispectral absorber is fabricated and its reflection responses are measured to verify designed performance.

• Journal of the Mineralogical Society of Korea
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• v.30 no.2
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• pp.59-70
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• 2017

$SiO_2$ is one of the most abundant constituents of the Earth's crust and mantle. Probing its electronic structures at high pressures is essential to understand their elastic and thermodynamic properties in the Earth's interior. The in situ high-pressure x-ray Raman scattering (XRS) experiment has been effective in providing detailed bonding transitions of the low-z materials under extreme compression. However, the relationship between the local atomic structures and XRS features at high pressure has not been fully established. The ab initio calculations have been used to overcome such experimental difficulties. Here we report the partial density of states (PDOS) of O atoms and the O K-edge XRS spectra of ${\alpha}-quartz$, ${\alpha}-cristobalite$, and $CaCl_2$-type $SiO_2$ phases calculated using ab initio calculations based on the full-potential linearized augmented plane wave (FP-LAPW) method. The unoccupied O PDOSs of the $CaCl_2$-type $SiO_2$ calculated with and without applying the core-hole effects present significantly distinctive features. The unoccupied O p states of the ${\alpha}-quartz$, ${\alpha}-cristobalite$ and $CaCl_2$-type $SiO_2$ calculated with considering the core-hole effect present similar features to their calculated O K-edge XRS spectra. This confirms that characteristic features in the O K-edge XRS stem from the electronic transition from 1s to unoccupied 2p states. The current results indicate that the core-hole effects should be taken in to consideration to calculate the precise O K-edge XRS features of the $SiO_2$ polymorphs at high pressure. Furthermore, we also calculated O K-edge XRS spectrum for $CaCl_2$-type $SiO_2$ at ~63 GPa. As the experimental spectra for these high pressure phases are not currently available, the current results for the $CaCl_2$-type $SiO_2$ provide useful prospect to predict in situ high-pressure XRS spectra.

• Journal of the Korean Magnetics Society
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• v.18 no.6
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• pp.211-216
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• 2008

The effects of Si impurity on electronic structures and magnetism of bcc Fe are investigated by using a first-principles method by considering spin-orbit coupling. In order to describe the Si impurity, a 27 atomic bcc Fe supercell has been considered. The Kohn-Sham equation was solved in terms of the all-electron full-potential linearized augmented plane wave (FLAPW) method within the generalized gradient approximation (GGA). The effects of spin-orbit coupling were calculated self-consistently by considering spin-diagonal terms based on second variation method. For the ferromagnetic (FM) state without considering SOC, the spin magnetic moment of the Si impurity was calculated to be $-0.143{\mu}B$, while the magnetic moments of Fe atoms were calculated to be $2.214{\mu}B$, $2.327{\mu}B$, and $2.354{\mu}B$ in away from the Si atom, respectively. However, the FM state with considering SOC, the spin magnetic moment of the Si impurity was calculated to be $-0.144{\mu}B$, which is not affected significantly by SOC, but the spin magnetic moments of Fe atoms were calculated $2.189{\mu}B$, $2.310{\mu}B$, and $2.325{\mu}B$, respectively, which are much reduced value compared to those of the FM state without SOC. Comparing the total charge density and spin density, those features are thought to be originated by the screening distortions of the Fe $t_{2g}$ orbital, which can be obtained by considering SOC.

• Culinary science and hospitality research
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• v.22 no.5
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• pp.151-166
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• 2016

The purpose of this study is to understand the influence of Chinese customer coffee sought benefits on satisfaction with, and attachment and loyalty to Korean coffee shops. Based on a total of 200 samples obtained for empirical research from 10 Mar. to 25 July, 2015, of self-administrated questionaries completed by patrons in Beijing, Shanghai, Haerbin in China, data were analyzed for frequency, exploratory factor analysis, reliability analysis, correlation analysis, multiple regression and hierarchical multiple regression analysis. The results of this study are summarized as follows. First, it was found that Chinese customer sought pursuits (functional & experimental benefits, symbolic benefit) had an effect on satisfaction of Korea coffee shop. Second, satisfaction influenced Korean coffee shop attachment and loyalty. Third, Korean wave attitude had a mediating effect between satisfaction, attachment and loyalty. From the results, we can conclude following implications: First, by providing atmosphere of South Korea, menu, barista service, we can predict that Korean coffee brands can prevail in competition through active promotions of their brands. Second, Korean coffee brands can make a strategy that includes providing full service from trained South Korean baristas and hosting talk shows between baristas from South Korea. Third, providing the opportunity to visit South Korea for local cafe tours is a good social event. These results will help control marketing strategies in China. Limitations and future research directions are also discussed.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.6
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• pp.73-79
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• 2008

Economic growth, industrialization and urbanization have made society more vulnerable than ever to seismic hazard in Korea. Although Korea has not experienced severe damage due to earthquakes during the last few decades, there is little doubt of the potential for large earthquakes in Korea as documented in the historical literature. As we see no immediate promise of short-term earthquake prediction with current science and technology, earthquake early warning systems attract more and more attention as a practical measure to mitigate damage from earthquakes. Earthquake early warning systems provide a few seconds to tens of seconds of warning time before the onset of strong ground shaking. To achieve rapid earthquake location, we propose to take full advantage of information from existing seismic networks; by using P wave arrival times at two nearest stations from the earthquake hypocenter and also information that P waves have not yet arrived at other stations. Ten earthquakes in the Korean peninsula and its vicinity are selected for the feasibility study. We observed that location results are not reliable when earthquakes occur outside of the seismic network. Earthquakes inside the seismic network, however, can be located very rapidly for the purpose of earthquake early warning. Seoul metropolitan area may secure $10{\sim}50$ seconds of warning time before any strong shaking starts for certain events. Carefully orchestrated actions during the given warning time should be able to reduce hazard and mitigate damages due to potentially disastrous earthquakes.

• The Research Journal of the Costume Culture
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• v.19 no.2
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• pp.283-295
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• 2011

This study deals with the interchange with art that is contained in the works of Yves Saint Laurent, and it is disclosed through his works that modern fashion is part of expressive art while pursuing creative function as a work of art. The study has been performed on the basis of the references, the pictures of his works and interviews posted in domestic and overseas fashion magazines such as Vogue, Fashion News, Mode & Mode, Gap, Collections, etc. Regarding the scope of this study, it specifically deals with works he created from 1958 until 2002, when he announced his last collection. The results of the study show that with respect to Post-Impressionism, his works were greatly affected by van Gogh(who had used colors as active media in depicting his internal mental state) which gave birth to gorgeous and handicraft-like 'Couture-style clothes'. With respects to Fauvism, the works of Matisse also had an impact on Yves Saint Laurent, who added a sense of fauvism in his works through the use of colors, motif, or full reproduction of images from paintings. We see the influence of cubism upon Laurent when we examine his works of 'clothes with artistic value,' which utilized applique, beaded decoration, patchwork, embroidered patterns, relief-like ornaments, etc. using motif or objet much as we see in the works of Picasso and Braque, artists who expressed a new dimension of the formative arts. Laurent's use of neoplasticism, or plainness of painting, demonstrates a new formative art on the three-dimensional human body by using the works of Mondrian, which consist of black lines and primary colors, although generally Laurent's 'neoplastic'works differed from the works of Mondrian by more actively utilizing the lines and colors when designing dress and its ornament. In addition, the paintings and poems of surrealism artists and poets were directly used in the clothes or their images were sometimes borrowed. In order to express respect toward the spirit of surrealism and its artists, the human body motifs such as lips and eyes(which were frequently used by the surrealism artists) were applied to embroidery, printing and beaded decoration. Finally, being inspired by such Pop artists as Andy Warhol, Roy Lichtenstein and Tom Wesselman, Laurent further emphasized the aesthetic value of the popular consumer image in his own work, resulting in the wide recognition of the designs of Yves Saint Laurent as representing the new wave of the Pop Art school.

• Journal of the Korean GEO-environmental Society
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• v.18 no.4
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• pp.13-21
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• 2017

Ballasted track has been used as track system for more than 100 years. Ballasted track has advantages of low construction cost, flexible maintenance, low noise and vibration, and so on. However, ballasted track leads to continuous settlement which causes maintenance. Recently, increase in speed, traffic volume, and weight of train requires more frequent maintenance. Fouling, well-known phenomenon of accumulation of fine materials due to intrusion of subgrade and breakage of ballast materials, expedites the settlement (i.e., irregular settlement) of track. Ground Penetrating Radar (GPR) can be one of non-destructive tools that can evaluate fouling level of ballast. In this paper, a gain function based on the attenuation characteristics of ballast material is suggested in conjunction with Hilbert transform. Lab box tests and full-scale tests indicate that the suggested method reasonably classifies clean, fouled layers, and subgrade. However, additional study to eliminate effect of sleeper and to include the scattering features of the electromagnetic wave in ballast voids should be required in order to enhance the accuracy.

• Progress in Medical Physics
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• v.29 no.1
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• pp.29-41
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• 2018

The objective of this study was to evaluate the chemical exchange saturation transfer (CEST) effect of amino acids and neurotransmitters, which exist in the human brain, depending on the concentration, pH, and amplitude of the saturation radiofrequency field. Phantoms were developed with asparagine (Asn), ${\gamma}-aminobutyric$ acid (GABA), glutamate (Glu), glycine (Gly), and myoinositol (MI). Each chemical had three different concentrations of 10, 30, and 50 mM and three different pH values of 5.6, 6.2, and 7.4. Full Z-spectrum CEST images for each phantom were acquired with a continuous-wave radiofrequency (RF) saturation pulse with two different $B_1$ amplitudes of $2{\mu}T$ and $4{\mu}T$ using an animal 9.4T MRI system. A voxel-based CEST asymmetry was mapped to evaluate exchangeable protons based on amide (-NH), amine ($-NH_2$), and hydroxyl (-OH) groups for the five target molecules. For all target molecules, the CEST effect was increased with increasing concentration and B1 amplitude; however, the CEST effect with varying pH displayed a different trend depending on the characteristics of the molecule. On CEST asymmetric maps, Glu and MI were well visualized around 3.0 and 0.9 ppm, respectively, and were well separated macroscopically at a pH of 7.4. The exchange rates of Asn, Glu, BABA, and Gly usually decreased with increasing pH. The CEST effect was dependent on the concentration, acidity of the target molecules, and B1 amplitude of the saturation RF pulse. The CEST effect for Asn can be observed in a 9.4T MRI system. The results of this study are based on applying the CEST technique in patients with neurodegenerative diseases when proteins in the brain are increased with disease progression.