• Title/Summary/Keyword: 가상의

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Analysis of Lateral Behavior of Offshore Wind Turbine Monopile Foundation in Sandy Soil (사질토에 근입된 해상풍력 모노파일 기초의 횡방향 거동 분석)

  • Jang, Hwa Sup;Kim, Ho Sun;Kwak, Yeon Min;Park, Jae Hyun
    • Journal of Korean Society of Steel Construction
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    • v.25 no.4
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    • pp.421-430
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    • 2013
  • To predict behaviors of offshore wind turbines which are highly laterally loaded structures and to design them rationally, evaluating the soil-foundation interaction is important. Nowadays, there are many soil modeling methods for structural analysis of general structures subjected to vertical loads, but using the methods without any consideration for design of a monopile foundation is eschewed because it might cause wrong structural design due to the deferent loading state. In this paper, we identify the differences of the member forces and displacements by design methods. The results show that fixed end method is barely suitable for monopile design in terms of checking the serviceability because it underestimate the lateral displacement. Fixed end method and stiffness matrix method underestimate the member forces, whereas virtual fixed end method overestimates them. The results of p-y curve method and coefficient of subgrade reaction method are similar to the results of 3D soil modeling method, and 2D soil modeling method overestimates the displacement and member forces as compared with other methods.

A Study on Signal Control Algorithms using Internal Metering for an Oversaturated Network (내부 미터링을 이용한 과포화 네트워크 신호제어 알고리즘 연구)

  • Song, Myeong-Gyun;Lee, Yeong-In
    • Journal of Korean Society of Transportation
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    • v.25 no.6
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    • pp.185-196
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    • 2007
  • The aim of this research is to develop a signal control algorithm using internal metering to minimize total delay that vehicles go through, in case a network is oversaturated. To calculate total delay on the network, the authors first detect vehicles' arrivals and departures in the network through the detecting system, and chase the vehicles' flow in the links with a platoon dispersion model. Following these, the authors calculate the queue length in all the inks of the network through the chase of vehicles, deduce the stopped time delay, and finally convert the stopped time delay to the approach delay with a time-space diagram. Based on this calculated delay, an algorithm that calculates the level of the internal metering necessary to minimize the deduced approach delay is suggested. To verify effectiveness of this suggested algorithm, the authors also conduct simulation with the micro-simulator VISSIM. The result of the simulation shows that the average delay per vehicle is 82.3 sec/veh and this delay is lower than COSMOS (89.9sec/veh) and TOD (99.1sec/veh). It is concluded that this new signal control algorithm suggested in this paper is more effective in controlling an oversaturated network.

Dose Characteristics of Stereotactic Radiosurgery in High Energy Linear Accelerator Proton Beam (고에너지 선형가속기에 의한 입체방사선수술의 선량특성)

  • Choi, Tae-Jin;Kim, Ok-Bae
    • Radiation Oncology Journal
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    • v.10 no.2
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    • pp.137-145
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    • 1992
  • Three-dimensional dose calculations based on CT images are fundamental to stereotactic radiosurgery for small intracranial tumor. In our stereotactic radiosurgery program, irradiations have been performed using the 6 MV photon beam of linear accelerator after stereotactic CT investigations of the target center through the beam's-eye view and the coordinates of BRW frame converted to that of radiosurgery. Also we can describe the tumor diameter and the shape in three dimensional configuration. Non-coplanar irradiation technique was developed that it consists of a combination of a moving field with a gantry angle of $140^{\circ}$, and a horizontal couch angle of $200^{\circ}C$ around the isocenter. In this radiosurgery technique, we provide the patient head setup in the base-ring holder and rotate around body axis. The total gantry moving range shows angle of 2520 degrees via two different types of gantry movement in a plane perpendicular to the axis of patient. The 3-D isodose curves overlapped to the tumor contours in screen and analytic dose profiles in calculation area were provided to calculate the thickness of $80\%$ of tumor center dose to $20\%$ of that. Furtheremore we provided the 3-D dose profiles in entire calculation plane. In this experiments, measured isodose curves in phantom irradiation have shown very similiar to that of computer generations.

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Competitiveness and Yield Loss Prediction of Water-seeded Rice by Densities of Scirpus juncoides Roxb (담수직파논 올챙이고랭이 발생밀도에 따른 경합 및 쌀 수량예측)

  • Won, Jong-Gun;Ahn, Duok-Jong;Kim, Se-Jong;Kwon, Oh-Do;Moon, Byeong-Chul;Park, Jae-Eup
    • Korean Journal of Weed Science
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    • v.30 no.1
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    • pp.43-49
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    • 2010
  • This study was conducted to predict the rice yield loss and determine the economic threshold levels for water direct seeded rice from competition of the most serious weeds, Scirpus juncoides Roxb. (bulrush) and Echinochlor crusgalli L. (barnyardgrass) in Daegu of Korea. To predict crop yield as a function of weed density used a rectangular hyperbola, and determine their economic threshold levels used the equation developed by Cousens. The rice yield loss model of S. juncoides was predicted as y = 466 / (1+0.00188x), $R^2$ = 0.933 and that of E. crusgalli was y = 458 / (1+0.02402x), $R^2$ = 0.973. In comparison of the competitiveness represented by parameter ${\beta}$, it was 0.001884 in S. juncoides and 0.02402 in E. crusgalli. Economic threshold calculated using Cousens' equation was negatively related to the competitiveness of weed. So that the economic threshold of S. juncoides was 13.4 and that of E. crusgalli was 1.07 plants per $m^2$.

Optimal Cost Design of Pipe Network Systems Using Genetic Algorithms (遺傳子 알고리즘을 이용한 管網시스템의 最適費用 設計)

  • Park, Yeong-Su;Kim, Jong-U;Kim, Tae-Gyun;Kim, Jung-Hun
    • Journal of Korea Water Resources Association
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    • v.32 no.1
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    • pp.71-81
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    • 1999
  • The objective of this study is to develop a model which can design an optimal pipe network system of least cost while satisfying all the design constraints including hydraulic constraints using a genetic algorithm technique. Hydraulic constraints interfaced with the simulation program(KYPIPE) checked feasible solution region. Genetic algorithm(GA) technique is a relatively new optimization technique. The GA is known as a very powerful search and optimization technique especially when solving nonlinear programming problems. The model developed in this study selects optimal pipe diameters in the form of commercial discrete sizes using the pipe diameters and the pumping powers as decision variables. The model not only determines the optimal diameters and pumping powers of pipe network system but also satisfies the discharge and pressure requirements at demanding nodes. The model has been applied to an imaginary and an existing pipe network systems. One system is adopted from journal papers which has been used as an example network by many other researchers. Comparison of the results shows compatibility of the model developed in this study. The model is also applied to a system in Goyang city in order to check the model applicability to finding of optimal pumping powers. It has been found that the developed model can be successfully applied to optimal design of pipe network systems in a relatively simple manner.

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Prediction of Shore Tide level using Artificial Neural Network (인공신경망을 이용한 해안 조위예측)

  • Rhee Kyoung Hoon;Moon Byoung Seok;Kim Tae Kyoung;Oh jong yang
    • Proceedings of the Korea Water Resources Association Conference
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    • 2005.05b
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    • pp.1068-1072
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    • 2005
  • 조석이란, 해면의 완만한 주기적 승강을 말하며, 보통 그 승강은 1일 약 2회이나, 곳에 따라서는 1일 1회의 곳도 있다. 조석에 있어서는 이 밖에 수일의 주기를 갖는 약간 불규칙한 승강, 반년, 또는 1년을 주기로 하는 다소 규칙적인 승강까지 포함하여 취급한다. 그러나, 각 항만마다 갖는 특정적인 주기인 수분내지 수십분의 주기의 승강은 조석으로 취급하지 않는다. 조석은 해양의 제현상 중에서 예측가능성이 가장 큰 현장으로 이는 조석이 천체의 운행과 연관되기 때문이다. 조석이란 지구로부터 일정한 거리에서 각 고유의 속도를 가지는 적도상을 운행하는 무수의 가상천체에 기인하는 규칙적인 개개의 조석을 합성한 것이며 이 개개의 조석을 분조(Constituent)라 한다. 여기에서 사용되는 신경망 모형은 입력과 출력으로 구성되는 블랙박스 모형으로서 하나의 시스템을 병렬적으로 비선형적으로 구축할 수 있다는 장점 때문에 과거 하천유역의 강우-유출과정에서의 경우 유출현상을 해석하고 유출과정을 모형화 하기 위해 사용하였다. 본 연구에서는 기존의 조위 예측방법인 조화분석법이 아닌 인공신경망을 이용하여 조위예측을 실시하였다. 학습이라는 최적화 과정을 통해 구조와 기능이 복잡한 자연현상을 그대로 받아들여 축적시킴으로써 이를 지식으로 현상에 대한 재현능력이 뛰어나고, 또한 신경회로망의 연상기억능력에 적용하여 수학적으로 표현이 불가능한 불확실한 조위곡선에 적용하기에 유리한 장점을 가지고 있다. 본 연구의 목적은 과거 조위이론을 통해 이루었던 조위예측을 우리가 알기 쉬운 여러 기후인자(해면기압, 풍향, 풍속, 음력 등)에 따른 조위곡선을 예측하기 위해 신경망 모형을 이용하여 여수지역의 조위에 적용하여 비교 분석하고자 한다. May가 제안한 공식을 더 확장하여 적용할 수 있는 실험 공식으로 개선하였으며 다양한 조건에 대한 실험을 수행하여 보다 정밀한 공식으로 개선할 수 있었다.$10,924m^3/s$ 및 $10,075m^3/s$로서 실험 I의 $2,757m^3/s$에 비해 통수능이 많이 개선되었음을 알 수 있다.함을 알 수 있다. 상수관로 설계 기준에서는 관로내 수압을 $1.5\~4.0kg/cm^2$으로 나타내고 있는데 $6kg/cm^2$보다 과수압을 나타내는 경우가 $100\%$로 밸브를 개방하였을 때보다 $60\%,\;80\%$ 개방하였을 때가 더 빈번히 발생하고 있으므로 대상지역의 밸브 개폐는 $100\%$ 개방하는 것이 선계기준에 적합한 것으로 나타났다. 밸브 개폐에 따른 수압 변화를 모의한 결과 밸브 개폐도를 적절히 유지하여 필요수량의 확보 및 누수방지대책에 활용할 수 있을 것으로 판단된다.8R(mm)(r^2=0.84)$로 지수적으로 증가하는 경향을 나타내었다. 유거수량은 토성별로 양토를 1.0으로 기준할 때 사양토가 0.86으로 가장 작았고, 식양토 1.09, 식토 1.15로 평가되어 침투수에 비해 토성별 차이가 크게 나타났다. 이는 토성이 세립질일 수록 유거수의 저항이 작기 때문으로 생각된다. 경사에 따라서는 경사도가 증가할수록 증가하였으며 $10\% 경사일 때를 기준으로 $Ro(mm)=Ro_{10}{\times}0.797{\times}e^{-0.021s(\%)}$로 나타났다.천성 승모판 폐쇄 부전등을 초래하는 심각한 선

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Development and Assessment of Flow Nomograph for the Real-time Flood Forecasting in Cheonggye Stream (청계천 실시간 홍수예보를 위한 Flow Nomograph 개발 및 평가)

  • Bae, Deg-Hyo;Shim, Jae Bum;Yoon, Seong-Sim
    • Journal of Korea Water Resources Association
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    • v.45 no.11
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    • pp.1107-1119
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    • 2012
  • The objectives of this study are to develop the flow nomograph for real-time flood forecasting and to assess its applicability in restored Cheonggye stream. The Cheonggye stream basin has the high impermeability and short concentration time and complicated hydrological characteristics. Therefore, the flood prediction method using runoff model is ineffective due to the limit of forecast. Flow nomograph which is able to forecast flood only with rainfall information. To set the forecast criteria of flow nomograph at selected flood forecast points and calculated criterion flood water level for each point, and in order to reflect various flood events set up simulated rainfall scenario and calculated rainfall intensity and rainfall duration time for each condition of rainfall. Besides, using a rating curve, determined scope of flood discharge following criterion flood water level and using SWMM model calculated flood discharge for each forecasting point. Using rainfall information following rainfall scenario calculated above and flood discharge following criterion flood water level developed flow nomograph and evaluated it by applying it to real flood event. As a result of performing this study, the applicability of flow nomograph to the basin of Cheonggye stream appeared to be high. In the future, it is reckoned to have high applicability as a method of prediction of flood of urban stream basin like Cheonggye stream.

A Study for Medical Mineral Reaction Controls on Artificial Body Fluid Composition: Gastric Juice-Cinnabar Reaction and Concentration of Mercury Complex (가상체액에 대한 광물약의 반응특성 모델링 ; 위액-주사 반응과 수은착물의 농도)

  • 박맹언;김선옥
    • Journal of the Mineralogical Society of Korea
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    • v.12 no.1
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    • pp.43-53
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    • 1999
  • The medical mineral menas a single mineral or a complex of minerals. It is natural material. using the medical action of he major or the minor elements, and traditional medicine stuff which has been used since long time ago. Jusa, cinnabar as the mineral name, is the product of the hydrothermal process. It is used to relax the body and cure high blood pressure, apoplexy and cardiopathy. Jusais the major component of "An shin hwan" and "Woo hwang chung shim hwan" nowadays because it has such an excellent calm effect. In addition, it is used to cure cancers such as esophageal cancer and gastric cancer. Jusa composed of mercuric sulfide causes mercury poisoning such as Minamata disease. It is dealt with mineralogical property and chemical composition medical stuff in Korea and China, as well asmercury poisoning and medical action of Jusa in this study. In order to predct accumulation of the interior of the body of the major and minor elements in Jusa, leaching experiment of Jusa by artificial gastric juice was done as well as thermodynamic reaction modelling to know concentration of each species of body fluid. The minor elements of 24 species such as As, Pb, Cd, a and Fe by leaching reaction of Jusa and artificial gastric juice were leached. We can know the fact that as is less than 1 ppm, Hg is less than 25 ppm and Cd and m are not detected. In addition, mercury exists as species of Hg2+, HgCl+, HgCl2, HgCl3-, HgCl42-, HgClOH, HgS(H2S)2, Hg(HS)3-, HgS22-, HgOH and Hg(OH)2 by reaction modelling between Jusa and artificial gastric juice. The concentration of sulfide complexes is 24.2 ppm and that of others is less than 10 ppm. According to increasing pH, the concentration of HgS(H2S)2, Hg(HS)3+, HgS22- and Hg(OH)2 increases, whereas the concentration of HgCl+, HgCl2, HgCl3- and HgCl42- decreases. Therefore, Jusa is very useful for the development of new medicine because it is possible to predict formation of the body species and species accumulation on mercury known as a toxic element and concentration changes of toxicity and efficiency.city and efficiency.

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Current Status of Elementary Students' Internet Addition: Differences according to Students' Gender and Grade (초등학생의 인터넷 중독 실태: 성과 학년별 차이를 중심으로)

  • Kim, Hyeong-Man;Lee, Bo-Ram;Jo, Mi-Heon
    • 한국정보교육학회:학술대회논문집
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    • 2010.08a
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    • pp.1-8
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    • 2010
  • With recent surge of Internet use, many people become concerned with side effects of Internet. Especially Internet addiction has become a significant issue. As the rate of teenagers' Internet use is higher than the rates of other age groups, and Internet takes an important part in teenagers' everyday lives, many people become concerned with Internet addition. Internet addiction is salient even among elementary school students. The purpose of this study is to grasp the realities of elementary students' Internet addiction using an evaluation tool developed for elementary school students, and to analyze differences in the addiction rate according to students' gender and grade. A survey was conducted to 989 5th and 6th graders selected from nationwide schools. The results of this study show that 5.0% of the students are in the stage of serious addiction, and 15.7% in the stage of early addiction. In addition, significant differences are found between boys and girls and between 5th graders and 6th graders.

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Occurrence and Genesis of Amphiboles in Hornblende Gabbro in Guwoonri, Hwacheon and in Otanri, Chuncheon (화천 구운리와 춘천 오탄리 일대에 분포하는 각섬석 반려암체내에 존재하는 각섬석류의 산출양상 및 생성작용)

  • Kim, Guan-Young;Park, Young-Rok
    • The Journal of the Petrological Society of Korea
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    • v.18 no.2
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    • pp.79-91
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    • 2009
  • Jurassic hornblende gabbo intrusives are distributed in Otanri, Chuncheon, and in Guwoonri, Hwacheon located in the northern part of Gyeonggi Massif. The intrusives composed mainly of amphiboles and plagioclase can be divided into two distinct rocks depending on the shape of amphiboles: (i) subspherical amphibole gabbro which has subspherical amphibole phenocryst as a major mafic phase(Sag); (ii) prismatic amphibole gabbro which has prismatic amphiboles as a principal mafic mineral(Pag). Subspherical amphiboles in Sag have higher Cr content and higher Mg($Mg+Fe^{2+}$) ratio relative to the prismatic amphiboles in Pag. This is indicative of conversion of pyroxene into amphibole with pyroxene pseudomorph. Oxygen isotopic results of plagioclase and amphibole separated from the hornblende gabbro suggest that theses minerals have experienced oxygen isotopic exchange with relatively heavy-$^{18}O$fluid for a long period, and magmatic fluid has been involved in the formation of subspherical amphiboles. Amphiboles in hornblende gabbro are composed of distinct species of pargasite, magnesiohornblende, actinolite, which formed at different stages.