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Estimation of resistance coefficient of PHC bored pile by Load Test II (재하시험에 의한 PHC 매입말뚝의 저항계수 산정 II)

  • Park, Jong-Bae;Park, Yong-Boo;Kwon, Young-Hwan
    • Land and Housing Review
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    • v.9 no.3
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    • pp.1-8
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    • 2018
  • In Europe and the United States, the use of limit states design has almost been established for pile foundation design. According to the global trend, the Ministry of Land, Transport and Maritime Affairs has established the basic design criteria of the bridge under the limit state design method. However, it is difficult to reflect on the design right now because of lack of research on resistance coefficient of the pile method and ground condition. In this study, to obtain the resistance coefficient of PHC bored pile which is widely used in Korea, the bearing capacity calculated by the LH design standard and the bridge design standard method, the static load test(21 times) and the dynamic load test(EOID 21 times, Restrike 21) The reliability analysis was performed on the results. The analysis of the resistance coefficient of PHC bored pile by loading test was analyzed by adding more than two times data. As a result, the resistance coefficient obtained from the static load test(ultimate bearing capacity) was 0.64 ~ 0.83 according to the design formula and the target reliability index, and the resistance coefficient obtained from the dynamic load test(ultimate bearing capacity) was 0.42~0.55. Respectively. The resistance coefficient obtained from the modified bearing capacity of dynamic load test(EOID's ultimate end bearing capacity + restrike's ultimate skin bearing capacity) was 0.55~0.71, which was reduced to about 14% when compared with the resistance coefficient obtained by the static load test(ultimate bearing capacity). As a result of the addition of the data, the resistivity coefficient was not changed significantly, even if the data were increased more than 2 times by the same value or 0.04 as the previous resistance coefficient. In conclusion, the overall resistance coefficient calculated by the static load test and dynamic load tests in this study is larger than the resistance coefficient of 0.3 suggested by the bridge design standard(2015).

Evaluation of near-realtime weekly root-zone Soil Moisture Index (SMI) for the extreme climate monitoring web-service across East Asia (동아시아 이상기후 감시 서비스를 위한 지면모형 기반 준실시간 토양수분지수평가)

  • Chun, Jong Ahn;Lee, Eunjeong;Kim, Daeha;Kim, Seon Tae;Lee, Woo-Seop
    • Journal of Korea Water Resources Association
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    • v.53 no.6
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    • pp.409-416
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    • 2020
  • An extreme climate monitoring is essential to the reduction of socioeconomic damages from extreme events. The objective of this study was to produce the near-realtime weekly root-zone Soil Moisture Index (SMI) on the basis of soil moisture using the Noah 3.3 Land Surface Model (LSM) for potentially monitoring extreme drought events. The Yangtze basin was selected to evaluate the Noah LSM performance for the East Asia region (15-60°N, 70-150°E) and the evapotranspiration (ET) and sensible heat flux (SH) were compared with ET and SH from FluxNet and with ET from FluxCom, Global Land Evaporation Amsterdam Model (GLEAM), ERA-5, and Generalized Complementary Relationship (GCR). For the ET, the coefficients of determination (R2) were higher than 0.96, while the R2 value for the SH was 0.71 with slightly lower than those. A time series of the weekly root-zone SMI revealed that the regions with Extreme drought had been expanded from the northern part of East China to the entire East China between July to October 2019. The trend analysis of the number of extreme drought events showed that extreme drought events in spring had reduced in South Korea over the past 20 years, while those in fall had a tendency to increase. It is concluded that this study can be useful to reduce the socioeconomic damages resulted from climate extremes by comprehensively characterizing extreme drought events.

Projecting future hydrological and ecological droughts with the climate and land use scenarios over the Korean peninsula (기후 및 토지이용 변화 시나리오 기반 한반도 미래 수문학적 및 생태학적 가뭄 전망)

  • Lee, Jaehyeong;Kim, Yeonjoo;Chae, Yeora
    • Journal of Korea Water Resources Association
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    • v.53 no.6
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    • pp.427-436
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    • 2020
  • It is uncertain how global climate change will influence future drought characteristics over the Korean peninsula. This study aims to project the future droughts using climate change and land use change scenarios over the Korean peninsula with the land surface modeling system, i.e., Weather Research and Forecasting Model Hydrological modeling system (WRF-Hydro). The Representative Concentration Pathways (RCPs) 2.6 and 8.5 are used as future climate scenarios and the Shared Socio-economic Pathways (SSPs), specifically SSP2, is adopted for the land use scenario. The using Threshold Level Method (TLM), we identify future hydrological and ecological drought events with runoff and Net Primary Productivity (NPP), respectively, and assess drought characteristics of durations and intensities in different scenarios. Results show that the duration of drought is longer over RCP2.6-SSP2 for near future (2031-2050) and RCP8.5-SSP2 (2080-2099) for the far future for hydrological drought. On the other hand, RCP2.6-SSP2 for the far future and RCP8.5-SSP2 for the near future show longer duration for ecological drought. In addition, the drought intensities in both hydrological and ecological drought show different characteristics with the drought duration. The intensity of the hydrological droughts was greatly affected by threshold level methods and RCP2.6-SSP2 for far future shows the severest intensity. However, for ecological drought, the difference of the intensity among the threshold level is not significant and RCP2.6-SSP2 for near future and RCP2.6-SSP2 for near future show the severest intensity. This study suggests a possible future drought characteristics is in the Korea peninsula using combined climate and land use changes, which will help the community to understand and manage the future drought risks.

Rheological Characteristics of Hydrogen Fermented Food Waste and Review on the Agitation Intensity (음식물류폐기물 수소 발효액의 유변학적 특성과 교반강도 고찰)

  • Kim, Min-Gyun;Lee, Mo-Kwon;Im, Seong-Won;Shin, Sang-Ryong;Kim, Dong-Hoon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.25 no.4
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    • pp.41-50
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    • 2017
  • The design of proper agitation system is requisite in biological waste treatment and energy generation plant, which is affected by viscosity, impeller types, and power consumption. In the present work, hydrogen fermentation of food waste was conducted at various operational pHs (4.5~6.5) and substrate concentrations (10~50 g Carbo. COD/L), and the viscosity of fermented broth was analyzed. The $H_2$ yield significantly varied from 0.51 to $1.77mol\;H_2/mol\;hexose_{added}$ depending on the pH value, where the highest performance was achieved at pH 5.5. The viscosity gradually dropped with shear rate increase, indicating a shear thinning property. With the disintegration of carbohydrate, the viscosity dropped after fermentation, but it did not change depending on the operational pH. At the same pH level, the $H_2$ yield was not affected much, ranging $1.40{\sim}1.86mol\;H_2/mol\;hexose_{added}$ at 10~50 g Carbo. COD/L. The zero viscosity and infinite viscosity of fermented broth increased with substrate concentrations, from 10.4 to $346.2mPa{\cdot}s$, and from 1.7 to $5.3mPa{\cdot}s$, respectively. There was little difference in the viscosity value of fermented broth at 10 and 20 g Carbo. COD/L. As a result of designing the agitation intensity based on the experimental results, it is expected that the agitation intensity can be reduced during hydrogen fermentation. The initial and final agitation intensity of 30 g Carbo. COD/L in hydrogen fermentation were 26.0 and 10.0 rpm, respectively. As fermentation went on, the viscosity gradually decreased, indicating that the power consumption for agitation of food waste can be reduced.

Place-myth of The Scenic Beauty from Mt. Kumgang : The social nature and the travel geography of noted mountains ('금강산'에서 전승되는 아름다움의 장소신화 : 사회적 자연과 명산의 여행지리)

  • Shin, Sung Hee
    • Journal of the Korean association of regional geographers
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    • v.22 no.1
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    • pp.151-167
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    • 2016
  • Conventional social science typically regards the idea of a 'mountain' as part of 'nature' and a physical environment existing separately from, or prior to, human society and culture. However, in Korea, which is 70% mountainous land, the 'mountain' is part of a unique 'social nature'. This research develops the idea that in this context the mountain is a social nature and a cultural landscape which are tied heavily to the idea of travel. The article interrogates why the scenic beauties of Mt. Kumgang have been perceived and conveyed through multiple generations since the Chosun Dynasty period. Focusing on Mt. Kumgang, this article illustrates how strongly people have held dreams of mountain travel, for the whole life-time. Travel writings(or accounts of trips to the mountain) and artwork have played a particularly important role in creating Mt. Kumgang's reputation as the most beautiful mountain in the country. At the same time, the access to the mountain was often a dangerous adventure, with many travelers facing hunger and extreme physical challenges. As portrayed in writings and artwork, the overall effect of these dynamics was the creation of a socionatural place of striking beauty that even seemed to have mystical or magical fantasy. According to Confucian ideals, full appreciation of nature and its beauty was key to understanding the logics of the universe and to achieving a high moral standard, which contributed to decide to leave for the mountain as well. The essays, poems, and paintings of Mt. Kumgang since the Chosun Dynasty period that portrayed the mountain's beauty collectively served to produce the mountain as a socionatural landscape engendered with potent place-myths, important historical meaning, and strong aesthetic associations. Thus, the travel to the mountain seemed never completed over until travelers had completed various artistic representations to record and to memorize what they'd done and seen in Mt. Kumgang, which had been performed for the strong purpose of social sharing of the real the mountain's beauties and itinerary.

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Lithological Characteristics and Deterioration Diagnosis of Dosolammaaebulsang (Rock-carved Buddha Statue of Dosolam) in the Seonunsa Temple, Gochang, Korea (고창 선운사 도솔암마애불의 암석학적 특성과 손상도 진단)

  • Park, Sung-Mi;Ryu, Keong-Seok;Choi, Hee-Soo;Lee, Chan-Hee
    • Journal of Conservation Science
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    • v.27 no.1
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    • pp.101-114
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    • 2011
  • The rock-carved Buddha statue at Dosolam (Korea Treasure No. 1200) of the Seonunsa temple in Gochang is unique style sculptured on natural rock cliff of 13.0m height. The Buddha statue is composed of volcanic complex with tuff, dacitic tuff breccia, tuff bereccia and lithic tuff. Especially, the Buddha statue is characterized by hydrothermal alteration and fragmentation on the upper and lower part. As a result of damage diagnosis, exfoliation and detachment of physical weathering are high of 11.3% and 9.3%, respectively. Infrared thermography analysis, exfoliation and micro-cracks occurred in the measuring parts that have not been confirmed by naked eyes. Chemical index of alteration and weathering potential index of host rock for the Buddha statue are 55.16 to 64.01 and 6.14 to 9.92 which are represented within highly weathering degree. In surface, dark black, reddish brown and white discoloration are observed prominently in the lower. Brown discoloration 6.9% is highest. According to the P-XRF measurements, high concentration of Fe in common, in part of dark black discoloration was Mn, white and brown discoloration in part of S and Ca content were higher. Biological weathering that yellowish brown and dark gray crustoes lichenes appeared by 20.8% and 13.3%, respectively. Therefore, comprehensive deterioration rate of Buddha statue show physical damage by 21.2%, discoloration for inorganic contaminants by 10.8% and biological damage by 39.4%. Ultrasonic velocity measurement carried out of Buddha statue on the surface by 555 points. Measured value of ultrasonic velocity was about 2,273m/s(1,067 to 3,215m/s, and weathering coefficient is 0.5(0.4 to 0.8) that progress on MW(moderately weathered) to HW(highly weathered) grade of rocks.

An Outlook on Cereal Grains Production in South Korea Based on Crop Growth Simulation under the RCP8.5 Climate Change Scenarios (RCP8.5 기후조건의 작물생육모의에 근거한 우리나라 곡물생산 전망)

  • Kim, Dae-Jun;Kim, Soo-Ock;Moon, Kyung-Hwan;Yun, Jin-I.
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.14 no.3
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    • pp.132-141
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    • 2012
  • Climate change impact assessment of cereal crop production in South Korea was performed using land attributes and daily weather data at a farm scale as inputs to crop models. Farmlands in South Korea were grouped into 68 crop-simulation zone units (CZU) based on major mountains and rivers as well as existing land use information. Daily weather data at a 1-km grid spacing under the A1B- and RCP8.5 scenarios were generated stochastically to obtain decadal mean of daily data. These data were registered to the farmland grid cells and spatially averaged to represent climate conditions in each CZU. Monthly climate data for each decade in 2001~2100 were transformed to 30 sets of daily weather data for each CZU by using a stochastic weather generator. Soil data and crop management information for 68 CZU were used as inputs to the CERES-rice, CERE-barley and CROPGRO-soybean models calibrated to represent the genetic features of major domestic cultivars in South Korea. Results from the models suggested that the heading or flowering of rice, winter barley and soybean could be accelerated in the future. The grain-fill period of winter barley could be extended, resulting in much higher yield of winter barley in most CZUs than that of rice. Among the three major cereal grain crops in Korea, rice seems most vulnerable to negative impact of climate change, while little impact of climate change is expected on soybeans. Because a positive effect of climate change is projected for winter barley, policy in agricultural production should pay more attention to facilitate winter barley production as an adaptation strategy for the national food security.

A Sensitivity Analysis of JULES Land Surface Model for Two Major Ecosystems in Korea: Influence of Biophysical Parameters on the Simulation of Gross Primary Productivity and Ecosystem Respiration (한국의 두 주요 생태계에 대한 JULES 지면 모형의 민감도 분석: 일차생산량과 생태계 호흡의 모사에 미치는 생물리모수의 영향)

  • Jang, Ji-Hyeon;Hong, Jin-Kyu;Byun, Young-Hwa;Kwon, Hyo-Jung;Chae, Nam-Yi;Lim, Jong-Hwan;Kim, Joon
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.12 no.2
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    • pp.107-121
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    • 2010
  • We conducted a sensitivity test of Joint UK Land Environment Simulator (JULES), in which the influence of biophysical parameters on the simulation of gross primary productivity (GPP) and ecosystem respiration (RE) was investigated for two typical ecosystems in Korea. For this test, we employed the whole-year observation of eddy-covariance fluxes measured in 2006 at two KoFlux sites: (1) a deciduous forest in complex terrain in Gwangneung and (2) a farmland with heterogeneous mosaic patches in Haenam. Our analysis showed that the simulated GPP was most sensitive to the maximum rate of RuBP carboxylation and leaf nitrogen concentration for both ecosystems. RE was sensitive to wood biomass parameter for the deciduous forest in Gwangneung. For the mixed farmland in Haenam, however, RE was most sensitive to the maximum rate of RuBP carboxylation and leaf nitrogen concentration like the simulated GPP. For both sites, the JULES model overestimated both GPP and RE when the default values of input parameters were adopted. Considering the fact that the leaf nitrogen concentration observed at the deciduous forest site was only about 60% of its default value, the significant portion of the model's overestimation can be attributed to such a discrepancy in the input parameters. Our finding demonstrates that the abovementioned key biophysical parameters of the two ecosystems should be evaluated carefully prior to any simulation and interpretation of ecosystem carbon exchange in Korea.

Usefulness evaluation of Hybrid planning through dosimetric comparision of Three Dimensinal Conformal Radiation Radiotherapy and Hybrid planning for left breast cancer (유방암 환자의 방사선 치료시 Energy와 Wedge를 combine한 Hybrid plan의 유용성 평가)

  • Chae, Moon Ki;Park, Byung Soo;Ahn, Jong Ho;Song, Ki Won
    • The Journal of Korean Society for Radiation Therapy
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    • v.26 no.1
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    • pp.91-98
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    • 2014
  • Purpose : To compare the dosimetry for the left breast cancer treatment between three dimensional conformal radiation radiotherapy (3D-CRT) and Hybrid planning and to estimate usefulness of Hybrid planning Materials and Methods : Five patients with left breast cancer were included in the study. They were planned using several different radiotherapy techniques including: 1)open rectangular field, 2)tangential wedge-based field 3)field in field, 4)hybrid planning(energy, wedge combine). For each patient planning was using Light Speed RT-16 CT and PINNACLE planning system-ver.9.2. Hybrid plan was made using same system and using the same targets and optimization goals. We comparing the Homogeneity Index(HI), normal organs at the does-volume histogram(DVH) Results : In all plans, the Homogeneity Index(HI) of Hybrid planning was significantly better than other. Dose comparison of HI= 2D-RT:38.32, TW:38.32, FIF:29.22, HYBRID:30.57. 2D-RT, TW, FIF Hybrid$V_{75_-lung}$=112.33, 125.14, 121.3, 123.78. $V_{50_-lung}$=155.43, 159.62, 157.96, 159.06. $V_{25_-lung}$=199.86, 200.22, 198.65, 200.31. $V_{50_-heart}$=26.07, 27.1, 26.85, 27.17 $V_{30_-heart}$=33.71, 34.37, 34.15, 34.65 Conclusion : In summary, 3D-CRT, Hybrid planning techniques were found to have acceptableCTV coverage in our study. However the Hybrid planning increased radiation dose exposure to normal tissue. If you apply for treatment of inhomogeneity areas like lung, For best results will be achieved.

A Study on Expressing 3D Animation by Visual Direction : focused on 〈 How to train your dragon 〉 (시각적 연출에 의한 3D 입체 애니메이션 표현 연구: 〈드래곤 길들이기〉를 중심으로)

  • Kim, Jung-Hyun
    • Cartoon and Animation Studies
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    • s.26
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    • pp.1-30
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    • 2012
  • The purpose of animation is to give interesting stories to an audience through motion. To achieve the purpose, over the past century since its inception, animation has adopted many kinds of technologies, and thus developed diverse narrative methods and visual expression techniques. In addition, with the advancement of expression techniques, all elements making up animation have gradually been systemized, and at the same time, have helped express the worlds beyond the reality. As a result, people have faced the era when an audience can watch everything imaginated by an animation director on a big screen. These days, more efforts have been made in order for the audience to feel much more than enjoy pictures moving in a frame. In other words, the purpose of the animation is changing from the passive viewing of animation to feeling and sensing stuffs through the animation. In the center of the changing process is 3D technology which gives new interesting to an audience. Sometime ago, a 3D animation movie was produced in Korea. But it did not bring out box-office profits, for it failed to give satisfaction to an audience who expected high perfection and beauty being able to be rivalled to those of international 3D animation movies. The failure is attributable to the fact that the domestic 3D animation production industry is merely in the early stage, and has not sufficient human resources, technology, and experiences in producing 3D animation films. Moreover, the problem is that most studies on 3D focus on the technologies related to reenactment, but that few studies on the images, which an audience directly faces, have been conducted. Under the domestic circumstance, the study on stereoscopic image screen of , a 3D stereoscopic animation film which was released in 2010 and has been seen as the best successful 3D stereoscopic animation, is worthwhile. Thus this thesis conducted theoretical consideration and case analysis focusing on the visual direction that creates the pictures to deliver abundant three dimensional effect so that it can be used as a basic data when producing high quality-domestic 3D animation and training professional labor forces. In the result, it was found that the 3D animation was not a new area, but the area which has been expanded and changed by applying the characteristics of 3D image based on the principles of the existing media aesthetics. This study might be helpful to establish the foundation of the theoretical studies necessary for producing 3D animation contents for realizing the sense of reality.