• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.4
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• pp.135-146
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• 2019

Deep beam has high section modules compared with shallow beam of the same weight. However, deep beam has low rotational capacity and high possibility of brittle failure so it is not possible to apply deep beams with a long span to intermediate moment frames, which should exhibit a ductility of 0.02rad of a story drift angle of steel moment frames. Accordingly, KBC and AISC limit the beam depth for intermediate and special moment frame to 750mm and 920mm respectively. The purpose of this paper is to improve the seismic performance of intermediate moment frame with 1200mm depth beam. In order to enhance vulnerability of plastic deformation capacity of deeper beam, Multi-Reduced Taper Beam(MRTB) shape that thickness of beam flange is reinforced and at the same time some part of the beam flange width is weakened are proposed. Based on concept of multiple plastic hinge, MRTB is intended to satisfy the rotation requirement for intermediate moment frame by dividing total story drift into each hinge and to prevent the collapse of the main members by inducing local buckling and fracture at the plastic hinge location far away from connection. The seismic performance of MRTB is evaluated by cyclic load test with conventional connections type WUF-W, RBS and Haunch. Some of the proposed MRTB connection satisfies connection requirements for intermediate moment frame and shows improved the seismic performance compared to conventional connections.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.3
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• pp.23-29
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• 2002

A wall-frame type structural system has been widely used to make full use of a limited land in large cities to satisfy the several functional requirement in one building. However, this type of hybrid structure brought some problems due to the vertical discontinuity of a structural system. The response of a wall-frame type structural system having a deep transfer girder was observed. An arch system was introduced to replace the deep transfer girder. The adequacy of an arch system was observed for the various boundary conditions of a system. The proposed system was compared to a general transfer girder system by applying both gravity load and lateral load. It was observed that an arch system fairly distributes the stress without concentrating stress at a certain location of a system differently from the current transfer girder system. The moment decrement effect of a column can also be obtained by eliminating the large mass of a transfer girder. Also it was investigated that an arch system is more economical and effective than the current transfer girder system.

• Journal of the Korean earth science society
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• v.21 no.4
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• pp.449-468
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• 2000

The Ordovician Chongson Limestone deposited in the carbonate ramp to the rimmed shelf shows diverse diagenetic features. The marine diagenetic feature appears as isopachous cements surrounding ooids and peloids. Meteoric diagenetic features are recrystallized finely and coarsely crystalline calcite, evaporite casts filled with calcite, and isopachous sparry calcite surrounding ooid grains. Shallow burial diagenetic features include wispy seam, microstylolite, and dissolution seam whereas deep burial features include stylolite, burial cements. blocky calcite with twin lamellae, and poikilotopic calcite. Dolomites consist of very finely to finely crystalline mosaic dolomite formed as supratidal dolomite, disseminated dolomite of diverse origin, patchy dolomite formed from bioturbated mottles, and saddle dolomite of burial origin. Silicified features include calcite-replacing quartz and fracture-filling megaquartz. Burial cements characterized by poikilotopic texture show ${\delta}^{18}$O value of -10.4 %$_o$ PDB, ${\delta}^{13}$C value of -1.0%$_o$ PDB and 504ppm Sr, 3643ppm Fe, and 152ppm Mn concentrations. Finely and coarsely crystalline limestones show similar ${\delta}^{18}$O and ${\delta}^{13}$C value to those of burial cements; however, they show lower Sr and higher Fe and Mn concentrations than burial cements. This suggests that very finely and coarsely crystalline limestones were recrystallized in freshwater and then they were readjusted geochemically in the burial setting whereas the burial cements were formed in relatively high temperature and low water/rock ratio conditions. Very finely and finely crystalline mosaic dolomites with ${\delta}^{18}$O value of -8.2%$_o$ PDB, ${\delta}^{13}$C value of -1.9 %$_o$ PDB, and 213ppm Sr, 3654ppm Fe, and 114ppm Mn concentrations, respectively are interpreted to have been formed penecontemporaneously in supratidal flat and then recrystallized in the low water/rock ratio burial environment. Geochemical data suggest that the low water/rock ratio burial environment was the dominant diagenetic setting in the Chongson Limestone. The Chongson Limestone has experienced marine and meteoric diagenesis during early diagenesis. With deposition of Haengmae and Hoedongri formations part of the Chongson Limestone was buried beneath these formations and it experienced shallow burial diagenesis. During the Devonian the Chongson Limestone was tectonically deformed and subaerially exposed. During the Carboniferous to the Permian about 3.3km thick Pyongan Supergroup was deposited on the Chongson Limestone and the Chongson Limestone was in deep burial depths and stylolite, burial cements, blocky calcite and saddle dolomite were formed. After this burial event the Chongson Limestone was subaerially exposed during the Mesozoic and Cenozoic by three periods of tectonic disturbance including Songnim, Daebo and Bulguksa disturbance. Since the Bulguksa disturbance during Cretaceous and early Tertiary the Chongson Limestone has been subaerially exposed.

• Journal of Periodontal and Implant Science
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• v.37 no.sup2
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• pp.409-426
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• 2007

세균성 치태는 치은의 염증과 치주 조직 파괴를 동반하는 치주염의 주요한 인자로서 치주 조직 건강을 유지하기 위하여 적절한 치태 조절이 필요하다. 본 논문의 목적은 12주 동안 만성 초기 및 중등도 치주염 환자에서 치은염에 대한 임상 지수의 감소, interleukin-6 (IL-6) 농도와 치주질환 원인균인 Prevotella intermedia (P. intermedia), Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans)에 대한 소니케어 전동 칫솔의 효과를 일반 칫솔과 비교해 보고자 하는 데 있다. 총 82명의 환자를 선택하였으며, 30명은 일반 칫솔, 52명은 소니케어 전동 칫솔 군으로 분류하여 칫솔질 교육을 실시하였다. 전악을 전치부와 구치부로 나누어 초진, 1, 4, 12주에서의 치태, 치은 지수 및 탐침 시 출혈 여부를 조사하였으며, 가장 깊은 치주낭 탐침을 보이는 치아 3개를 선택하여 탐침 깊이와 부착 정도를 측정하였고, 선택된 치아에서 초진, 1, 12주에 채취된 샘플을 통해 치은열구액 내의 IL-6 농도와 P. intermedia, A. actinomycetemcomitans의 CT값을 추가적으로 조사하여 다음과 같은 결과를 얻었다. 1 소니케어 전동 칫솔과 일반 칫솔군 모두 치은 염증을 나타내는 임상 지수 (치태지수, 치은지수, 탐침 시 출혈)는 12주 기간 동안 유의한 감소 (p<0.05)를 보였으나, 전동 칫솔 군에서 통계학적으로 더욱 유의하게 (p<0.05) 나타났다. 2. 전치부를 제외한 구치부 치아에서 소니케어 전동 칫솔군은 12주 기간 동안 탐침 시 출혈의 감소가 통계학적으로 유의하게 (p<0.05) 나타났다. 3. 가장 깊은 치주낭 탐침 깊이를 보이는 3개의 선택된 치아에서 치주낭 탐침 깊이와 부착 정도는 두 군 모두 초진에 비해 유의한 감소 (p<0.05)를 보였다. 퍼센트 변화 비교에서 치주낭 탐침 깊이는 소니케어 전동 칫솔군이 $18.47{\pm}10.05%$, 일반 칫솔군이 $14.19{\pm}8.16%$로, 부착 정도는 소니케어 전동 칫솔군이 $24.26{\pm}12.51%$, 일반 칫솔군이 $15.65{\pm}9.92%$로 각각 나타났으나, 군 간 통계적 유의차는 보이지 않았다. 4. 치은열구액의 IL-6 농도는 두 군 모두 12주 기간 동안 통계적으로 유의한 감소 (p<0.05)를 나타내었다. 퍼센트 변화 비교에서 전동 칫솔군은 51%, 일반 칫솔군은 37%로 각각 나타났으나, 군 간 통계적 유의차는 보이지 않았다. 5. Prevotella intermedia, Actinobacillus actinomycetemcomitans의 관찰에서 두 군 모두 유의한 차이는 없었다. 위 결과를 통해 본 연구에서는 소니케어 전동 칫솔의 사용이 일반 칫솔에 비하여 만성 초기 및 중등도 치주염 환자에서 치태의 제거, 치은 염증 및 임상 지수의 감소에 유의한 효과가 있으며 IL-6의 감소 경향에도 효과가 있음을 관찰하였다.

• Journal of the Korea Institute of Building Construction
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• v.14 no.4
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• pp.336-342
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• 2014

Shear strengths of reinforced high strength concrete beams without web reinforcement are studied with experimental analysis of 10 specimen with 2.4 shear span-to-depth ratio (a/d) beams for 4 stages of concrete compressive stength over 60MPa comparing ultimate loads and shear stresses of ACI363R and KCI code equations. Expecially, concrete compressive strengths used in shear design were essentially limited to 10,000 psi (69MPa) by ACI363R and KCI Code. The modified Code equation's shear stresses of the specimen without the limit are compared with test results. The comparison between the modified exist Code equations results and test results are expected to show an available scope to apply in construction field and to give considerations of design and contraction.

• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.366-373
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• 2020

This study investigated habitat diversity changes by conducting weir operations at the Sejongbo site in the Geum River basin. High-resolution aerial photographs taken before and after the weir-opening operation were used for habitat analyses. We classified water and bar areas into 17 types, such as lotic habitats, including riffles, runs, and glides, and lentic habitats, including reservoirs, pools, bar-head backwaters, and bar ponds. Then, we estimated each habitat area quantitatively, calculated a habitat diversity index, and established a habitat diversity map. Our results indicated that after the weir-opening operation, lotic habitats and new types of shallow lentic habitats increased in the water area. In addition, for the bar area, bare lands without cultivation increased distinctively. Finally, we observed that the habitat diversity index drastically increased after the weir-opening operation, which could provide a relatively simple channel of diverse habitats.

• Journal of the Korea Concrete Institute
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• v.15 no.6
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• pp.820-828
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• 2003

Recent research has indicated that the current ACI shear provision provides unconservative predictions for large slender beams and beams with low level of longitudinal reinforcement, and conservative results for deep beams. To modify some problems of ACI shear provision, ultimate shear strength equation considering size effect and arch action to compute shear strength in high-strength concrete beams without stirrups is presented in this research. Three basic equations, namely size reduction factor, rho factor, and arch action factor, are derived from crack band model of fracture mechanics, analysis of previous some shear equations for longitudinal reinforcement ratio, and concrete strut described as linear prism in strut-tie model deep beams. Constants of basic equations are determined using statistical analysis of previous shear testing data. To verify proposed shear equation for each variable, effective depth, longitudinal reinforcement ratio, concrete compressive strength and shear span-to-depth ratio, about 300 experimental data are used and proposed shear equation is compared with ACI 318-99 code, CEB-FIP Model code, Kim &Park's equation and Zsutty's equation. The proposed shear equation is not only simpler than other shear equations, it is but also shown to be economical predictions and reasonable safety margin. Hence proposed shear strength equation is expected to be applied to practical shear design.

• Korean Journal of Plant Taxonomy
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• v.44 no.3
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• pp.171-174
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• 2014

A new species, Pseudostellaria baekdusanensis M. Kim (Caryophyllaceae), has been named and described from Mt. Baekdu of the Korean peninsula. Pseudostellaria baekdusanensis shares several characteristics (same size leaves, axillary or terminal flowers, emaginate petals, etc.) with its related species P. japonica (Korshinsky) Pax. It is, however, distinct from P. japonica which have large plant (25-35 cm), leaf blade margins and midveins with long hairs, shallow emaginate petal apex, (2) 3 styles, and cleistogamic flowers by having small plants (9-13 cm), leaf blade basal margins with long hairs, deep emaginate petal apex, 2 styles, and non-cleistogamic flowers.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.229-234
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• 2012

This paper presents channel measurements for wireless body area network(WBAN) and provides performance evaluation from the measurement. We measured the radio propagation in 2.45 GHz ISM band in an anechoic chamber according to various human movements and the position of transmit antennas. Two transmit antennas are mounted on different positions of human body for the purpose of comparing the diversity gain and correlation between the channels in $2{\times}1$ multiple-input single-output(MISO) systems. The experimental results show that the outage capacity is closely related with the correlation coefficient between channels in transmit diversity system.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.3
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• pp.154-161
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• 2017

The purpose of this study was to investigate the change of length, opening width, and number of openings effecting on topography change around artificial reefs under erosive wave condition. Hydraulic model test was conducted to see sediment transport around the structures and the relation among the installation condition of the artificial reefs, generated velocity, wave deformation, and topographic change was reviewed. Experimental results show that the sediment transport rate was reduced; however, the scour around the structures was increased under the condition of having a single opening compared to the structures having a plurality of openings which shows inversely proportional to the size of Lr/W.