• ETRI Journal
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• v.42 no.6
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• pp.827-836
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• 2020

Measuring the diffraction loss for high frequencies, long distances, and large diffraction angles is difficult because of the high path loss. Securing a well-controlled environment to avoid reflected waves also makes long-range diffraction measurements challenging. Thus, the prediction of diffraction loss at millimeter-wave frequency bands relies on theoretical models, such as the knife-edge diffraction (KED) and geometrical theory of diffraction (GTD) models; however, these models produce different diffraction losses even under the same environment. Our observations revealed that the KED model underestimated the diffraction loss in a large Fresnel-Kirchhoff diffraction parameter environment. We collected power-delay profiles when millimeter waves propagated over a building rooftop at millimeter-wave frequency bands and calculated the diffraction losses from the measurements while eliminating the multipath effects. Comparisons between the measurements and the KED and GTD diffraction-loss models are shown. Based on the measurements, an approximation model is also proposed that provides a simple method for calculating the diffraction loss using geometrical parameters.

• Journal of Fashion Business
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• v.27 no.5
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• pp.78-92
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• 2023

Fashion trends are actively disseminated through social media, which influences both their propagation and consumption. This study explored how users perceive subversive basic fashion in social media videos, by examining the associated concepts and characteristics. In addition, the factors contributing to the style's social media dissemination were identified and its distinctive features were analyzed. Through text mining analysis, 80 keywords were selected for semantic network and CONCOR analysis. TF-IDF and N-gram results indicate that subversive basic fashion involves transformative design techniques such as cutting or layering garments, emphasizing the body with thin fabrics, and creating bold visual effects. Topic modeling suggests that this fashion forms a subculture that resists mainstream norms, seeking individuality by creatively transforming the existing garments. CONCOR analysis categorized the style into six groups: forward-thinking unconventional fashion, bold and unique style, creative reworking, item utilization and combination, pursuit of easy and convenient fashion, and contemporary sensibility. Consumer actions, linked to social media, were shown to involve easily transforming and pursuing personalized styles. Furthermore, creating new styles through the existing clothing is seen as an economic and creative activity that fosters network formation and interaction. This study is significant as it addresses language expression limitations and subjectivity issues in fashion image analysis, revealing factors contributing to content reproduction through user-perceived design concepts and social media-conveyed fashion characteristics.

• Journal of Korean Society of Forest Science
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• v.90 no.2
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• pp.184-189
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• 2001

Multiple shoots were induced from in vitro shoot originated from winter bud of P. yedoensis from Jeju. Most explants grow in similar type among the five different media but affected by supplement of sucrose regardless of media. For mass-propagation various concentrations of BAP or $GA_3$ were treated in the medium respectively. BAP was very effective to produce multiple shoots and 3.5~9.5 shoots were formed on the explant. The shoots induced on the high levels of BAP have short internodes. No shoots were induced on the treatment of $GA_3$ but roots were induced on it. When $GA_3$ was supplemented with the medium containing BAP, multiple shoots were produced from the explants. The medium(WPM) containing with $0.5mg/{\ell}$ BAP and $4.0mg/{\ell}$ $GA_3$ was most effective to produce multiple shoots. When the explants were cultured for 8 weeks, 39.5 shoots were developed in average.

• Structural Engineering and Mechanics
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• v.61 no.2
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• pp.221-230
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• 2017

In this paper, we investigated the propagation of thermoelastic surface waves in fibre-reinforced anisotropic general viscoelastic media of higher order of nth order including time rate of strain under the influence of rotation. The general surface wave speed is derived to study the effectsof rotation andthermal onsurface waves. Particular cases for Stoneley, Love and Rayleighwaves are discussed.The results obtained in this investigation are more general in the sense that some earlier published results are obtained from our result as special cases. Our results for viscoelastic of order zero are well agreed to fibre-reinforced materials. Comparison was made with the results obtained in the presence and absence of rotation and parameters for fibre-reinforced of the material medium. It is also observed that, surface waves cannot propagate in a fast rotating medium.Numerical results for particular materials are given and illustrated graphically. The results indicate that the effect of rotation on fibre-reinforced anisotropic general viscoelastic media are very pronounced.

• Journal of the Korean Applied Science and Technology
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• v.23 no.1
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• pp.70-76
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• 2006

The influence of fluorophor, scatterer, absorber in turbid materials by light scattering were interpreted for the scattered fluorescence intensity and wavelength, it is studied the molecular property by laser induced fluorescence spectroscopy. It can be found that the effects of optical property are penentrated in scattering media by the optical $parameters({\mu}s$, ${\mu}a$, ${\mu}t$, ${\gamma}$, ${\rho})$. The value of scattering coefficient ${\mu}s$ is large appeared by means of the increasing particles of scattering, it can be found that the slope appears exponentially as a function of distance from laser source to detector. It may also utilize in designing the best model for oil chemistry, laser medicine and application of medical engineering.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.2
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• pp.77-85
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• 1998

Propagation of elastic surface waves in anisotropic media is considered in this study. An analytical technique is proposed to study the scattering of surface waves at the interface between two anisotropic quarter-spaces. The Green's function technique is used to derive a system of equations which can determine the scattering coefficients at the interface. A numerical study is carried out and the trade-offs between the material anisotropy and inhomogeneity are studied.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.197-202
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• 2007

Most of seismic reflection prospecting assumes subsurface formation to be homogeneous media. These models are not capable of estimating small scale heterogeneity which is verified by well log data or drilling core. And those synthetic seismograms by homogeneous media are limited to explain various changes at field data. So we developed a inhomogeneous velocity model which can estimate inhomogeneity of background medium to implement numerical modeling from homogeneous medium and inhomogeneous medium on the model. Background medium using three autocorrelation functions in order to generate inhomogeneous velocity media was according to dominant wavelength of background medium and correlation length of random medium. And then we compared shot gathers. The results show that numerical modeling implemented at inhomogeneous medium depicts complex wave propagation of field data.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2619-2621
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• 2001

This study proposes a new efficient MAC(media access control) protocol to establish the ultrasonic communication network for under water vehicles, which ensures a certain level of maximum throughput regardless of the propagation delay of ultrasonic and allows fast data transmission through the multiple ultrasonic communication channel. In this study, a media access control protocol for underwater communication network that allows 'peer-to-peer' communication between a surface ship and multiple underwater system is designed, and the proposed control protocol is implementde for its verification.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05a
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• pp.373-376
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• 2003

의상 애니메이션은 영화나 게임, 의류 전자상거래 동 다양한 분야에서 활용될 수 있는 컴퓨터 그래픽스 분야에서 연구되어왔던 기술이다. 하드웨어의 발달과 빠르고 효율적인 물리학적 모델과 수치적 적분법 등의 등장으로 옷감의 움직임을 모델링 하는 데에 그치지 않고, 더 나아가 실제 옷감처럼 자연스러운 움직임을 얻고자하는 방향으로 연구의 초점이 맞추어졌다. 본 연구에서는 사실적인 의상 애니메이션을 위해 역전파 신경망을 이용하여 실제 옷감소재를 자동으로 평가하는 옷감소재 자동 평가 알고리즘을 제시하고 실험하였다. 실험을 통해 실제 옷감과 유사한 가상 옷감을 생성할 수 있었다.

• The Journal of Korean Association of Computer Education
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• v.17 no.2
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• pp.31-38
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• 2014

This paper reveals continuity of related events which are occurred and changing from moment to moment accident/events collected from various social media channels. Among them, we especially define the events which have big social influence as "issue event" and investigate the type and characteristics of continuous issue event for each domain. We also introduce a automatic issue detection system in social media text. Based on the extracted issue event results in a particular domain, we analyse the continuity of those events by illustrating in time and place-axis. Furthermore, we identify the relationship between social media in terms of issue events propagation.