• Title/Summary/Keyword: ODe

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Thermal Analysis on a Satellite Box during Launch Stage by Analytical Solution

  • Choi, Joon-Min;Kim, Hui-Kyung;Hyun, Bum-Seok
    • International Journal of Aeronautical and Space Sciences
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    • v.4 no.2
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    • pp.17-25
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    • 2003
  • Simple methods are developed to predict temperatures of a satellite box during launch stage. The box is mounted on outer surface of satellite and directly exposed to space thermal environment for the time period from fairing jettison to separation. These simple methods are to solve a 1st order ordinary differential equation (ODE) which is simplified from the governing equation after applying several assumptions. The existence of analytical solution for the 1st order ODE is determined depending on treatment of time-dependent molecular heating term. Even for the case that the analytical solution is not available due to the time dependent term, the 1st order ODE can be solved by relatively simple numerical techniques. The temperature difference between two different approaches (analytical and numerical solutions) is relatively small (Jess than $1^{\circ}C$ along the time line) when they are applied to STSAT-I launch scenario. The present methods can be generally used as tools to quickly check whether a satellite box is safe against space environment during the launch stage for the case that the detailed thermal analysis is not available.

The Development of Overhead Crane Simulator Using Open Source Physics Engine (오픈소스 물리엔진을 이용한 천장 크레인 시뮬레이터 개발)

  • Ok, Soo-Yol;Kim, Sung-Kil
    • Journal of Korea Game Society
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    • v.9 no.5
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    • pp.95-104
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    • 2009
  • Recently, increasing numbers of games and simulators are being implemented by employing the physically-based modeling techniques for better realism. In this paper, we propose the implementation techniques for overhead crane simulator based on ODE, the well-known open source dynamic engine. By comparing the dynamic behavior of the proposed system with a commercial engine based simulator, the physical plausibility and the effectiveness of the ODE based OHC simulator are verified. We expect the proposed the OHC simulator can be successfully utilized for virtual training in various educational institutes.

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Analytical Analysis of PT Ferroresonance in the Transient-State (과도상태에서 PT 철공진의 해석적 분석)

  • Kang, Yong-Cheol;Lee, Byung-Eun;Zheng, Tai-Ying;Kim, Yeon-Hee
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.5
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    • pp.860-865
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    • 2010
  • When a circuit breaker is opened, a large capacitance around the buses, the circuit breaker and the potential transformer (PT) might cause PT ferroresonance. During PT ferroresonance, the iron core repeats saturation and unsaturation even though the supplied voltage is a rated voltage. This paper describes an analytical analysis of PT ferroresonance in the transient-state. To analyze ferroresonance analytically, the iron core is modelled by a simplified two-segment core model in this paper. Thus, a nonlinear ordinary differential equation (ODE) for the flux linkage is changed into a linear ODE with constant coefficients, which enables an analytical analysis. In this simplified model, each state, which is either saturated or unsaturated state, corresponds to one of the three modes, i.e. overdamping, critical damping and underdamping. The flux linkage and the voltage in each state are obtained analytically by solving the linear ODE with constant coefficients. The proposed transient analysis is effective in the more understanding of ferroresonance and thus can be used to design a ferroresonance prevention or suppression circuit of a PT.

A Study on the Educational Plan of Business Chinese Speaking by Using the Method of Storytelling and Role-play - Focused on Chinese Drama - (스토리텔링과 롤 플레이 기법을 통한 비즈니스 중국어 말하기 교육방안 탐색 - 드라마를 중심으로 -)

  • Li, Xiaohui;Li, Zhangpei;Park, Changun
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.9 no.5
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    • pp.273-280
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    • 2019
  • The main purpose of this study is to reveal the educational value of the Chinese drama and present a concrete and feasible Chinese speaking teaching-learning programme targeted at intermediate level Chinese learners through storytelling and role-play. There is some advice for Chinese speaking teaching-learning by using Chinese dramas. Firstly, applying various techniques actively such as storytelling and role play, not only could it help to correct Chinese speaking pronunciation, but it could also help students to make up and express their ideas as free as possible. Secondly, it's necessary to accord with the teaching objectives of Chinese speaking, students' actual level and requirements to select Chinese dramas as Chinese speaking teaching-learning materials. Thirdly, it's noteworthy that teachers should select Chinese dramas with various genres or theme according to social development to promote the fun of class and maximize the educational value of Chinese dramas as teaching-learning materials.

Relationship between Urban Identity and Time and Space - Focusing on , Zhang Lu's Film (도시 정체성과 시공간 구조의 관계 -장률(張律)의 영화 <군산: 거위를 노래하다>를 중심으로)

  • Cho, Myung-Ki
    • Journal of Popular Narrative
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    • v.27 no.3
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    • pp.151-191
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    • 2021
  • This paper examines what is the content of Gusan's urban identity, represented by the film and how the contents and aspects of this city's identity interact with the structure of the films' discourse. weaves Gunsan and Seoul into continuously reorganized cities based on an interactive relation, rather than literal ones. Seoul in which the time for a film narrative is closed is converted into the starting point for tour to Gunsan. The both points in which audiences' ex post return occurs are the starting point for the time for the film discourse and the other point in which the title is suggested. The journey-type of the narrative structure in this film is a3-dimensional spiral-shaped, rather than a 2-dimensional circular regression. embodies the characteristics and the identity and apriority of two cities, based on such a spiral-shaped temporal and spatial structure. Seoul severs the relation between grand narrative/collective memory and small narrative/individual memory as an agnostic one, in other words, it is a city that cuts off cities, relations and memory and rejects the continuity of memory. On the other hand, Gunsan is a city in which both grand and small narrative and collective and individual memory coexist and both split and isolated mind are cured and mutually consoled. It describes Gunsan as the surplus space as a being for others, while expressing its identity as robust and literal thing. The film describes it as the field in which oppositional concepts such as historical interruption and continuity and spatial being for others and originality become 3-dimensional spiral ones, through the reciprocity between the narrative and the discourse structure. This paper has an implication, in that it examines how temporal and spatial relationship constituting the urban identity interacts with the structure of the film narrative.

A Study on Intersection Computation in Interval Arithmetic (인터벌 연산 기반의 곡면간 교차선 계산에 관한 연구)

  • Ko, Kwang-Hee
    • Korean Journal of Computational Design and Engineering
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    • v.15 no.3
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    • pp.178-188
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    • 2010
  • This paper addresses the problem of determining if two surfaces intersect tangentially or transversally in a mathematically consistent manner and approximating an intersection curve. When floating point arithmetic is used in the computation, due to the limited precision, it often happens that the decision for tangential and transversal intersection is not clear cut. To handle this problem, in this paper, interval arithmetic is proposed to use, which provides a mathematically consistent way for such decision. After the decision, the intersection is traced using the validated ODE solver, which runs in interval arithmetic. Then an iterative method is used for computing the accurate intersection point at a given arc-length of the intersection curve. The computed intersection points are then approximated by using a B-spline curve, which is provided as one instance of intersection curve for further geometric processing. Examples are provided to demonstrate the proposed method.

Research of a Virtual Reality 3D Operation Model for a Robot Contest (로봇경진대회의 가상현실 3D 운영 모델에 대한 연구)

  • Kim, Jin-Woo;Kim, Joo-Min;Kim, Dae-Won
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.1825_1826
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    • 2009
  • This paper is proposed to make a virtual reality 3D operation model including a robot model and an environment model for a robot contest. First of all, we make the robot model using Open Dynamics Engine(ODE), and the environment model similar to the robot contest. These ODE models are programmed by the C-language. Lastly, we perform simulations to verify the robot model and the environment model. As a result, it shows the possibility of models for the robot contest.

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