• Title/Summary/Keyword: Geometrical Characteristics

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Estimation of Attenuation Relationship Compatible with Damping Ratio of Rock Mass from Numerical Simulation (수치해석을 통한 진동감쇠식 맞춤형 암반의 감쇠비 산정)

  • Kim, Nag Young;Ryu, Jae-Ha;Ahn, Jae-Kwang;Park, Duhee;Son, Murak;Hwang, Young-Cheol
    • Journal of the Korean Geotechnical Society
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    • v.31 no.4
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    • pp.45-55
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    • 2015
  • The stability of the adjcent structures or slopes under blasting is typically evaluated using an empirical vibration attenuation curve or dynamic numerical analysis. To perform a dynamic analysis, it is necessary to determine the blast load and the damping ratio of rock mass. Various empirical methods have been proposed for the blast load. However, a study on representative values of damping ratio of a rock mass has not yet been performed. Therefore, the damping ratio was either ignored or selected without a clear basis in performing a blast analysis. Selection of the dampring ratio for the rock mass is very difficult because the vibration propagation is influenced by the layout and properties of the rock joints. Besides, the vibration induced by blasting is propagated spherically, whereas plane waves are generated by an earthquake. Since the geometrical spreading causes additional attenuation, the damping ratio should be adjusted in the case of a 2D plane strain analysis. In this study, we proposed equivalent damping ratios for use in continuum 2D plane strain analyses. To this end, we performed 2D dynamic analyses for a wide range of rock stiffness and investigated the characteristics of blast vibration propagation. Based on numerical simulations, a correlation between the attenuation equation, shear wave velocity, and equivalent damping ratio of rock mass is presented. This novel approach is the first attempt to select the damping ratio from an attenuation relationship. The proposed chart is easy to be used and can be applied in practice.

A Study on the Mods-Look Expressed on the 21st Century Fashion (21세기 패션에 표현된 모즈 룩 연구)

  • Chu, Mi-Kyung;Kim, Soon-Ja
    • Journal of the Korean Society of Clothing and Textiles
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    • v.32 no.6
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    • pp.859-870
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    • 2008
  • The purpose of this study is to investigate the fashion reflecting the aesthetic consciousness of a generation and age spirit and to study Mods-Look aesthetically by analyzing how Mods-Look expressed on the fashion magazines(Collezioni Donna) from 2001 to 2006 developed into a new form. 1960's Mods-Look appeared in the well known collections such as New York, Paris, Milan in the form of crossover or with a changed style. Especially after 2000's, in addition to the British fashion, even a new word Mods Story was created to prominently express the free style of the Mods spirit. The expressive characteristics represent 1) minimal style, 2) sports casual style, 3) vintage style, 4) dandy & androgynous style. In conclusion, Mods-Look in 21st fashion used to be street fashion started from minority subculture after world war II, but now suit of that time, geometrical pattern and sensibility are becoming design sources for the various fashion market from high fashion to sports look. Therefore, as young people are becoming the center of society in new millenium, sensibility of that time will be reinterpreted to design and Mods-Look will not be limited to subculture but reflected in design development fulfilling people's taste and new future fashion sense by compromising the past and new trend.

Analysis of Intrafractional Mass Variabilities Using Deformable Image Registration Program (영상변조 프로그램을 이용한 호흡 위상 간 종양의 움직임 특성 분석)

  • Cho, Jeong-Hee;Kim, Joo-Hoo;Seo, Sun-Youl;Han, Dong-Kyoon
    • Journal of radiological science and technology
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    • v.35 no.2
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    • pp.173-181
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    • 2012
  • The aim of this study is to compare the geometric characteristics of the lung tumor, such as tumor centroid, HU change relative to breath phase, depending on tumor location and adhesion using 4DCT and deformable image registration program (MIMVista). The Y axis change was most significant and the mean Y axis centroid fluctuation was 7.32±6.88mm in lower lung tumor. The mean HU variation in lower lung mass has changed more than other locations, and its mean HU variation was 7.7±4.97 and non-adhered mass was more changed. Correlation for the mass volume between 3DCT and MIP was very high and its coefficient was 0.998. The effect of tumor location, adhesion and diaphragm excursion to geometric uncertainties was analyzed by linear regression model, it was influenced to mass deformation and geometrical variation so much except diaphragm excursion. but intra-fractional and inter-patient's uncertainties were great, so it couldn't find any exact deformation trend.

Study on Synthesis of 68GeO2 and Behavior of 68Ga3+ for Generator Column (Generator 컬럼용 68GeO2 합성 및 68Ga3+의 거동에 관한 연구)

  • Kim, Gun Gyun;Lee, Jun Young;Kim, Sang Wook;Hur, Min Gu;Yang, Seung Dae;Park, Jeong Hoon
    • Journal of Radiation Industry
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    • v.10 no.4
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    • pp.189-192
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    • 2016
  • 68Ga has emerged as a promising candidate for non-invasive diagnostic imaging within Positron Emission Tomography (PET) because of its advantageous radiochemical characteristics (t1/2=68min, β+ yield ~89%). 68Ga forms a stable chelation with various ligands and it is possible to be quickly and easily study using a 68Ge/68Ga generator. Commercial 68Ge/68Ga generators are chromatographic system using the inorganic materials such as alumina and tin dioxide which are employed as column matrixes for 68Ge. In this study, we tried out to make 68Ge/68Ga generator system with the 68GeO2 microstructures for column matrix. 68Ge tends to have stable bond with oxide as 68GeO2 microstructures. The 68GeO2 has been synthesized by hydrolysis of GeCl4 (sol-gel method) and characterized by X-ray diffraction and scanning electron microscope for geometrical analysis. The stability of GeO2 was tested using eluents with diverse solvents(water, ethanol and 0.1 N HCl). The radioactivity of 68Ga3+ in eluate through GeO2 was measured to prove a function as column material for a generator.

Seismic Fragility Analysis based on Material Uncertainties of I-Shape Curved Steel Girder Bridge under Gyeongju Earthquake (강재 재료 불확실성을 고려한 I형 곡선 거더 교량의 경주 지진 기반 지진 취약도 분석)

  • Jeon, Juntai;Ju, Bu-Seog;Son, Ho-Young
    • Journal of the Society of Disaster Information
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    • v.17 no.4
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    • pp.747-754
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    • 2021
  • Purpose: Seismic safety evaluation of a curved bridge must be performed since the curved bridges exhibit the complex behavior rather than the straight bridges, due to geometrical characteristics. In order to conduct the probabilistic seismic assessment of the curved bridge, Seismic fragility evaluation was performed using the uncertainty of the steel material properties of a curved bridge girde, in this study. Method: The finite element (FE) model using ABAQUS platform of the curved bridge girder was constructed, and the statistical parameters of steel materials presented in previous studies were used. 100 steel material models were sampled using the Latin Hypercube Sampling method. As an input ground motion in this study, seismic fragility evaluation was performed by the normalized scale of the Gyeongju earthquake to 0.2g, 0.5g, 0.8g, 1.2g, and 1.5g. Result: As a result of the seismic fragility evaluation of the curved girder, it was found that there was no failure up to 0.03g corresponding to the limit state of allowable stress design, but the failure was started from 0.11g associated with using limit state design. Conclusion: In this study, seismic fragility evaluation was performed considering steel materials uncertainties. Further it must be considered the seismic fragility of the curved bridge using both the uncertainties of input motions and material properties.

Seismic Reliability Analysis of Offshore Wind Turbine with Twisted Tripod Support using Subset Simulation Method (부분집합 시뮬레이션 방법을 이용한 꼬인 삼각대 지지구조를 갖는 해상풍력발전기의 지진 신뢰성 해석)

  • Park, Kwang-Yeun;Park, Wonsuk
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.32 no.2
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    • pp.125-132
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    • 2019
  • This paper presents a seismic reliability analysis method for an offshore wind turbine with a twisted tripod support structure under earthquake loading. A three dimensional dynamic finite element model is proposed to consider the nonlinearity of the ground-pile interactions and the geometrical characteristics of the twisted tripod support structure where out-of-plane displacement occurs even under in-plane lateral loadings. For the evaluation of seismic reliability, the failure probability was calculated for the maximum horizontal displacement of the pile head, which is calculated from time history analysis using artificial earthquakes for the design return periods. The application of the subset simulation method using the Markov Chain Monte Carlo(MCMC) sampling is proposed for efficient reliability analysis considering the limit state equation evaluation by the nonlinear time history analysis. The proposed method can be applied to the reliability evaluation and design criteria development of the offshore wind turbine with twisted tripod support structure in which two dimensional models and static analysis can not produce accurate results.

A Command of French and anti-style used in Lee Sang's poetic work (이상(Lee Sang)의 시작품에 구사되는 프랑스어와 반문체)

  • Lee, Byung Soo
    • Cross-Cultural Studies
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    • v.49
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    • pp.229-248
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    • 2017
  • This paper is a study on French of Lee Sang's poems called metaphysical scandals in Korean poetry. Is poetic language he used a common poetic word or a non-poetic word in French? What kind of harmony do words and sentences composed of French have with Korean, Chinese character, and non-poetic word? Based on these questions, we analyzed a command of French, that is symbolic, geometrical, and pictorial French as well as repetitive and parallel constitution used in form of words and sentences. In Lee Sang's poems, as a result, the use of French is seen as a mixture of non-poetic word. It shows characteristics that reject traditional native language and the creation of poetry. In his poems, French is also an important factor of avant-garde poetic material and experimental creation technique. In his poems, French is used as a special tool to express internal conflicts of the poet. Lee Sang showed experimental style that could not be found in modern Korean literature by using signifier and signifed that french language has.

Effect of Intersecting Angles of Rock Fractures on Solute Mixing at Fracture Junction (암반단열의 교차각이 교차점에서의 용질의 혼합에 미치는 영향)

  • Kim, Dahye;Yeo, In Wook
    • Economic and Environmental Geology
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    • v.54 no.4
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    • pp.465-473
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    • 2021
  • This numerical study aims at analyzing the effect of flow characteristics, caused by geometrical features such as intersecting angles, on solute mixing at fracture junctions. It showed that not only Pe, the ratio of advection to diffusion, but also the intersecting angles played an important role in solute mixing at the junction. For the intersection angles less than 90°, the fluid flowed to the outlet in the same direction as the injected flow direction, which increased the contact at the junction with the streamlines coming from the different inlets. On the other hand, for the intersecting angles greater than 90°, the fluid flowed out to the outlet opposite to the flow direction in the inlet, leading to minimizing the contact at the junction. Therefore, in the former case, solute mixing occurred even at high Pe, and in the latter case, solutes transport along the streamlines even at low Pe. For Pe < 1, the complete mixing model was known to occur, but for the intersecting angle greater than 150°, no complete solute mixing occurred. Overall, the transition from the complete mixing model to the streamline-routing model occurred for Pe = 0.1 - 100, but it highly depended on the intersecting angles. Specifically, the transition occurred at Pe = 0.1 - 10 for intersecting angles ≧ 150° and at Pe = 10 - 100 for intersecting angles ≦ 30°. For Pe > 100, the streamline-routing model was dominant regardless of intersecting angles. For Pe > 1,000, the complete streamline-routing model appeared only for the intersecting angles greater than 150°. For the intersecting angles less than 150°, the streamline-routing model dominated over the complete solute mixing, but solute mixing still occurred at the fracture junction.

Animal Home Range Estimators - A Review and a Case Study - (동물 행동권 분석 방법론 고찰 - 괭이갈매기 사례 분석과 시사점 -)

  • Lee, Sung-Joo;Lee, Who-Seung
    • Korean Journal of Environment and Ecology
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    • v.36 no.2
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    • pp.202-216
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    • 2022
  • Animals exhibit certain behaviors and movement patterns as they react to their internal needs, external stimuli, and surrounding environments. They have a bounded range in which they mostly spend their time, and it is referred to as a home range. Based on the fact that the home range is a critical area for the survival and preservation of species, there has been a growing body of research on developing more precise home range estimation methods to use the estimated ranges as a ground for establishing an effective conservation policy since the early 1940s. Recent rapid advancements in telemetry technology that resulted in the presence of autocorrelation between locations with short time intervals revealed the limitations of the existing estimators. Many novel estimators have been developed to compensate for it by incorporating autocorrelation in calculating home ranges. However, studies on the animal home range are still in their early stage in Korea, and newly developed methodologies have not yet been adopted. Therefore, this study aims to introduce the foreign home range estimation methods and foster domestic research activities on home ranges. Firstly, we compared and contemplated seven estimators by categorizing them into geometrical and statistical methodologies and then divided them into estimators that assume independent observations and those that consider autocorrelation in each category. After that, the home ranges of black-tailed gulls (Larus crassirostris) were calculated using GPS tracking data for the month of June and derived home range estimators by applying the methodology introduced in this study. We analyzed and compared the results to discuss the strengths and weaknesses of each method. Lastly, we proposed a guideline that can help researchers choose an appropriate estimator for home range calculation based on the animal location data characteristics and analysis purpose.

Inference of the Probability Distribution of Phase Difference and the Path Duration of Ground Motion from Markov Envelope (Markov Envelope를 이용한 지진동의 위상차 확률분포와 전파지연시간의 추정)

  • Choi, Hang;Yoon, Byung-Ick
    • Journal of the Earthquake Engineering Society of Korea
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    • v.26 no.5
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    • pp.191-202
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    • 2022
  • Markov envelope as a theoretical solution of the parabolic wave equation with Markov approximation for the von Kármán type random medium is studied and approximated with the convolution of two probability density functions (pdf) of normal and gamma distributions considering the previous studies on the applications of Radiative Transfer Theory (RTT) and the analysis results of earthquake records. Through the approximation with gamma pdf, the constant shape parameter of 2 was determined regardless of the source distance ro. This finding means that the scattering process has the property of an inhomogeneous single-scattering Poisson process, unlike the previous studies, which resulted in a homogeneous multiple-scattering Poisson process. Approximated Markov envelope can be treated as the normalized mean square (MS) envelope for ground acceleration because of the flat source Fourier spectrum. Based on such characteristics, the path duration is estimated from the approximated MS envelope and compared to the empirical formula derived by Boore and Thompson. The results clearly show that the path duration increases proportionately to ro1/2-ro2, and the peak value of the RMS envelope is attenuated by exp (-0.0033ro), excluding the geometrical attenuation. The attenuation slope for ro≤100 km is quite similar to that of effective attenuation for shallow crustal earthquakes, and it may be difficult to distinguish the contribution of intrinsic attenuation from effective attenuation. Slowly varying dispersive delay, also called the medium effect, represented by regular pdf, governs the path duration for the source distance shorter than 100 km. Moreover, the diffraction term, also called the distance effect because of scattering, fully controls the path duration beyond the source distance of 300 km and has a steep gradient compared to the medium effect. Source distance 100-300 km is a transition range of the path duration governing effect from random medium to distance. This means that the scattering may not be the prime cause of peak attenuation and envelope broadening for the source distance of less than 200 km. Furthermore, it is also shown that normal distribution is appropriate for the probability distribution of phase difference, as asserted in the previous studies.