• Title/Summary/Keyword: One-dimensional model

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STUDY ON THERMAL MODELING METHODS OF A CYLINDRICAL GROUND OBJECT CONSIDERING THE SPECTRAL SOLAR RADIATION THROUGH THE ATMOSPHERE

  • Choi Jun-Hyuk;Choi Mi-Na;Gil Tae-Jun;Kim Tae-Kuk
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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    • pp.205-208
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    • 2005
  • This research is aimed at the development of a software that predicts the surface temperature profiles of three-dimensional objects on the ground considering the spectral solar radiation through the atmosphere. The thermal modelling is essential for identifying the objects on the scenes obtained from the satellites. And the temperature distribution on the objects is necessary to obtain their infrared images in contrast to the background. We developed a software that could be used to model the thermal problems of the ground objects irradiated by the spectral solar radiation. This software can be used to handle the conduction within the object as a one-dimensional mode into the depth or as a three-dimensional mode through the media. LOWTRAN7 is used to model the spectral solar radiation including the direct and diffuse solar radiances. In this paper, temperature distributions on the objects obtained by using the one-dimensional and the three-dimensional thermal models are compared with each other to examine the applicability of the relatively easy-to-apply one-dimensional model.

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엔드밀링의 효과적인 절삭력 모델과 NC 검증시스템으로의 응용 (Fast Force Algorithm of End Milling Processes and Its Application to the NC Verification System)

  • 김찬봉;양민양
    • 대한기계학회논문집
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    • 제19권7호
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    • pp.1555-1562
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    • 1995
  • This study represents the non-dimensional cutting force model. With the non-dimensional cutting force model it is possible to estimate efficiently the maximum cutting force during one revolution of cutter. Using the non-dimensional cutting force model, the feed rate and spindle speed are adjusted so as to satisfy the maximum cutting force and maximum machining error. To verify the accuracy and efficiency of the non-dimensional cutting force model, a series of experiments were conducted, and experimental results proved and verified the non-dimensional cutting force model. The NC toolpath verification system developed in this paper uses the non-dimensional cutting force model, so that it is effective for calculating the cutting force and adjusting the cutting conditions.

모형 그물에 대한 어군행동의 수직 모델링에 관한 연구 - 해산어에 의한 수치 모델의 적합성 검토 - (A Study on the Numerical Modeling of the Fish Behavior to the Model Net - Fitness Examination of Numerical Model by the Marine Fish -)

  • 장호영;이주희
    • 수산해양기술연구
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    • 제34권2호
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    • pp.174-184
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    • 1998
  • In order to accumulate fundamental. data for control of fishes’ behavior at the real fishing ground, the fitness of the numerical model for describing the behavior of fishes was examined by the marine fish. Mullet, Mugil cephalus were used as experimental fishes. The numerical model of fishes’ behavior presented in our earlier paper was modified on the vertical movement of fish school. For the comparision of parameters of the modified numerical model between mullet and rainbow trout, the estimated values of parameters were identified with dimension. The fitness of the modified numerical model was examined by the comparision between experiment and simulation on the several indexes represented by fishes’ swimming characteristics. The obtained result are summarized a follows : 1. The non-dimensional parameter a’ of propulsive force and kb’ of interactive force by the experiment without model net showed a similarity, but the non-dimensional parameter k sub(c’) of schooling force for rainbow trout was lager than one for mullet and the non-dimensional parameter k sub(w’) of repulsive force for mullet was lager than one for rainbow trout. 2. The non-dimensional parameter a’ and k sub(b’) for rainbow trout by the experiment with model net were a little lager than ones for mullet, but non-dimensional parameter k sub(c’) and k sub(w’) for mullet were lager than ones for rainbow trout. 3. The non-dimensional parameter k sub(c’) and k sub(b’) showed the largest and the smallest value among the non-dimensional parameters for rainbow trout and mullet, respectively. 4. The fitness of the modified numerical model was confirmed by means of the compulsion between experiment and simulation on the swimming trajectory of fishes, the mean distance of individual from wall, the mean swimming speed, the mean swimming depth and the mean distance between the nearest individuals. Especially, the similarity of mean swimming depth was improved by using the modified numerical model.

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지표면의 특성을 고려한 대기경계층내의 열수지 parameter 추정 -열수지 parameter를 이용한 중규모 순환의 수치예측- (Estimation of the Heat Budget Parameter in the Atmospheric Boundary Layer considering the Characteristics of Soil Surface)

  • 이화운;정유근
    • 한국환경과학회지
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    • 제5권6호
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    • pp.727-738
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    • 1996
  • An one dimensional atmosphere-canopy-soil interaction model is developed to estimate of the heat budget parameter in the atmospheric boundary layer. The canopy model is composed of the three balance equations of energy, temperature, moisture at ground surface and canopy layer with three independent variables of Tf(foliage temperature), Tg(ground temperature), and qg(ground specific humidity). The model was verilied by comparative study with OSUID(Oregon State University One Dimensional Model) proved in HAPEX-MOBILHY experiment. Also we applied this model in two dimensional land-sea breeze circulation. According to the results of this study, surface characteristics considering canopy acted importantly upon the simulation of meso-scale circulation. The factors which used in the numerical experiment are as follows ; the change for a sort of soil(sand and peat), the change for shielding factor, and the change for a kind of vegetation.

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일차원 혈류해석을 위한 스펙트럴 요소 모델링 (Spectral Element modeling for the one-dimensional blood flow analysis)

  • 장인준;이우식
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2008년도 정기 학술대회
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    • pp.152-155
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    • 2008
  • The blood flow characteristics have been closely related to various cardiovascular diseases, it is very important to predict them accurate enough in an efficient way. Thus, this paper proposes a one-dimensional spectral element model for the blood flow through blood vessels. The spectral element model is formulated by using the variational method. The nonlinear terms in spectral element model are all treated as the pseudo-force and an iterative solution method is applied in the frequency domain.

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1차원 모델에 의한 지중열교환기의 열거동 해석 (A Study on the Thermal Behavior of Vertical Borehole Heat Exchanger with 1-Dimensional Model)

  • 이세균;김대기;우정선;박상일
    • 한국태양에너지학회 논문집
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    • 제25권1호
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    • pp.97-104
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    • 2005
  • A one-dimensional heat transfer model for the vertical borehole system is derived in this study to predict the thermal behavior of the system and surrounding soil. In this model the U-tube is replaced with one effective tube of effective diameter which is surrounded by concentric grout region. All thermal resistances of borehole are counted in the grout region with effective thermal conductivity of grout. Effective thermal conductivity of grout and sand are calculated through parameter estimation. The validity of this model is accomplished through comparison of the predicted temperature profiles of the model with experimental data.

Discrete-Layer Model for Prediction of Free Edge Stresses in Laminated Composite Plates

  • Ahn, Jae-Seok;Woo, Kwang-Sung
    • 한국전산구조공학회논문집
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    • 제23권6호
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    • pp.615-626
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    • 2010
  • The discrete-layer model is proposed to analyze the edge-effect problem of laminates under extension and flexure. Based on three-dimensional elasticity theory, the displacement fields of each layer in a laminate have been treated discretely in terms of three displacement components across the thickness. The displacement fields at bottom and top surfaces within a layer are approximated by two-dimensional shape functions. Then two surfaces are connected by one-dimensional high order shape functions. Thus the p-convergent refinement on approximated one- and two-dimensional shape functions can be implemented independently of each other. The quality of present model is mostly determined by polynomial degrees of shape functions for given displacement fields. For nodal modes with physical meaning, the linear Lagrangian polynomials are considered. Additional modes without physical meaning, which are created by increasing nodeless degrees of shape functions, are derived from integrals of Legendre polynomials which have an orthogonality property. Also, it is assumed that mapping functions are linear in the light of shape of laminated plates. The results obtained by this proposed model are compared with those available in literatures. Especially, three-dimensional out-of-plane stresses in the interior and near the free edges are evaluated and convergence performance of the present model is established with the stress results.

Partition method of wall friction and interfacial drag force model for horizontal two-phase flows

  • Hibiki, Takashi;Jeong, Jae Jun
    • Nuclear Engineering and Technology
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    • 제54권4호
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    • pp.1495-1507
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    • 2022
  • The improvement of thermal-hydraulic analysis techniques is essential to ensure the safety and reliability of nuclear power plants. The one-dimensional two-fluid model has been adopted in state-of-the-art thermal-hydraulic system codes. Current constitutive equations used in the system codes reach a mature level. Some exceptions are the partition method of wall friction in the momentum equation of the two-fluid model and the interfacial drag force model for a horizontal two-phase flow. This study is focused on deriving the partition method of wall friction in the momentum equation of the two-fluid model and modeling the interfacial drag force model for a horizontal bubbly flow. The one-dimensional momentum equation in the two-fluid model is derived from the local momentum equation. The derived one-dimensional momentum equation demonstrates that total wall friction should be apportioned to gas and liquid phases based on the phasic volume fraction, which is the same as that used in the SPACE code. The constitutive equations for the interfacial drag force are also identified. Based on the assessments, the Rassame-Hibiki correlation, Hibiki-Ishii correlation, Ishii-Zuber correlation, and Rassame-Hibiki correlation are recommended for computing the distribution parameter, interfacial area concentration, drag coefficient, and relative velocity covariance of a horizontal bubbly flow, respectively.

열차 충돌에너지 흡수구조의 초기붕괴특성을 고려하기 위한 하중-변형 곡선 모델링 방법 (Modeling Method for the Force and Deformation Curve of Energy Absorbing Structures to Consider Initial Collapse Behaviour in Train Crash)

  • 김준우;구정서;임종순
    • 한국자동차공학회논문집
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    • 제18권3호
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    • pp.116-126
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    • 2010
  • The Korean rolling stock safety regulation stipulates that the collision deceleration of a car body should be maintained under average 5g and maximum 7.5g during train collisions. One-dimensional dynamic model of a full rake train, which is made up of nonlinear springs/bars-dampers-masses, is often used to estimate the collision decelerations of car bodies in a basic design stage. By the way, the previous studies have often used some average force-deformation curve for energy absorbing structures in rolling stock. Through this study, we intended to analyse how much the collision deceleration levels are influenced by the initial peak force modeling in the one-dimensional force-deformation curve. The numerical results of the one-dimensional dynamic model for the Korean High-Speed Train show that the initial peak force modeling gives significant effect on the collision deceleration levels. Therefore the peak force modeling of the force-deformation curve should be considered in one-dimensional dynamic model of a full rake train to evaluate the article 16 of the domestic rolling stock safety regulations.

Kano의 이원적 품질모형과 Timko의 만족계수를 활용한 공학교육의 질 향상 방안 탐색 (An Improvement Method of Engineering Education Quality using Kano's Dualistic Quality Model and Timko's Satisfaction Coefficient)

  • 허영주;예철해
    • 공학교육연구
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    • 제21권3호
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    • pp.31-37
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    • 2018
  • The purpose of this study is to develop a method to improve the quality of engineering education by using Kano's dualistic quality model and Timko's customer satisfaction coefficient. The results of the study are as follows. Firstly, the top priority for major education is improve 'smooth support of class medium' as an attractive and one-dimensional quality element, and 'use of various examples' and 'specialty improvement of major curriculum' as an one-dimensional quality element. Secondly, the top priority for general education is improve 'liberal education curriculum' as an attractive quality element 'use of various examples' as an one-dimensional quality element. Thirdly, the top priority for extra-curriculum is develop and provide 'study support program of student' and 'voluntary service'. Fourthly, the top priority for administrative service and facilities is improve 'increase of scholarship' and expand 'service of welfare facilities as dormitory and refectory' as an one-dimensional quality element.