• 제목/요약/키워드: body-space

검색결과 1,638건 처리시간 0.027초

LINEAR STABILITY OF TRIANGULAR EQUILIBRIUM POINTS IN THE PHOTOGRAVITATIONAL RESTRICTED THREE BODY PROBLEM WITH TRIAXIAL RIGID BODIES, WITH THE BIGGER ONE AN OBLATE SPHEROID AND SOURCE OF RADIATION

  • KUMAR, AVDHESH;ISHWAR, B.
    • 천문학논총
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    • 제30권2호
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    • pp.297-299
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    • 2015
  • In this paper we have examined the linear stability of triangular equilibrium points in the photogravitational restricted three body problem when both primaries are triaxial rigid bodies, the bigger one an oblate spheroid and source of radiation. The orbits about the Lagrangian equilibrium points are important for scientific investigation. A number of space missions have been completed and some are being proposed by various space agencies. We analyze the periodic motion in the neighbourhood of the Lagrangian equilibrium points as a function of the value of the mass parameter. Periodic orbits of an infinitesimal mass in the vicinity of the equilibrium points are studied analytically and numerically. The linear stability of triangular equilibrium points in the photogravitational restricted three body problem with Poynting-Robertson drag when both primaries are oblate spheroids has been examined by A. Kumar (2007). We have found the equations of motion and triangular equilibrium points for our problem. With the help of the characteristic equation we have discussed stability conditions. Finally, triangular equilibrium points are stable in the linear sense. It is further seen that the triangular points have long or short periodic elliptical orbits in the same range of ${\mu}$.

저속차량 차체의 구조해석 및 구조최적설계 (Structural Analysis and Optimization of a Low Speed Vehicle Body)

  • 신정규;심진욱;황상진;박경진
    • 한국자동차공학회논문집
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    • 제11권4호
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    • pp.68-78
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    • 2003
  • Recently, low speed vehicle (LSV) is beginning to appear for various usages. The body of the LSV is usually made of the aluminum space frame (ASF) type rather than the monocoque or unitary construction type. A pa.1 of the reason is that it is easier to reduce mass efficiently while the required stiffness and strength are maintained. A design flow for LSV is proposed. Design specifications for structural performances of LSV do not exist yet. Therefore, they are defined through a comparative study with general passenger automobiles. An optimization problem is formulated by the defined specifications. At first, one pillar which has an important role in structural performances is selected and the reinforcements of the pillar are determined from topology optimization to maximize the stiffness. At second, the thicknesses of cross sections are determined to minimize the mass of the body while design specifications are satisfied. The optimum solution is compared with an existing design. The optimization process has been performed using a commercial optimization software system, GENESIS 7.0.

FMS를 이용한 대전차 유도탄의 각속도 계산식 검증 (Verification of Missile Angular Velocity Calculation Using FMS)

  • 박어진;김완식;박찬국
    • 한국항공우주학회지
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    • 제37권10호
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    • pp.992-997
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    • 2009
  • 본 논문에서는 제한된 센서 조건에서 유도탄 동체의 각속도를 계산하는 법을 보이고 Flight Motion Simulator(FMS)를 이용한 각속도 계산식 검증을 다룬다. 일반적으로 유도탄 동체의 각속도는 동체에 탑재하는 각속도 자이로를 이용하여 측정하지만, 유도탄 동체에 탑재하는 관성 센서 중에 피치와 요 각속도 자이로가 없는 제한된 센서 조건을 가정한다. 이와 같은 제한된 센서 조건에서 김블 탐색기 자이로, 동체의 롤 각속도 자이로, 김블의 자세 측정값 및 자세 변화율을 이용하여 유도탄 동체의 각속도를 계산할 수 있음을 보인다. 제안한 각속도 계산식을 검증하기 위하여 FMS를 이용한 실험을 수행하였다.

Dynamic modeling and structural reliability of an aeroelastic launch vehicle

  • Pourtakdoust, Seid H.;Khodabaksh, A.H.
    • Advances in aircraft and spacecraft science
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    • 제9권3호
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    • pp.263-278
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    • 2022
  • The time-varying structural reliability of an aeroelastic launch vehicle subjected to stochastic parameters is investigated. The launch vehicle structure is under the combined action of several stochastic loads that include aerodynamics, thrust as well as internal combustion pressure. The launch vehicle's main body structural flexibility is modeled via the normal mode shapes of a free-free Euler beam, where the aerodynamic loadings on the vehicle are due to force on each incremental section of the vehicle. The rigid and elastic coupled nonlinear equations of motion are derived following the Lagrangian approach that results in a complete aeroelastic simulation for the prediction of the instantaneous launch vehicle rigid-body motion as well as the body elastic deformations. Reliability analysis has been performed based on two distinct limit state functions, defined as the maximum launch vehicle tip elastic deformation and also the maximum allowable stress occurring along the launch vehicle total length. In this fashion, the time-dependent reliability problem can be converted into an equivalent time-invariant reliability problem. Subsequently, the first-order reliability method, as well as the Monte Carlo simulation schemes, are employed to determine and verify the aeroelastic launch vehicle dynamic failure probability for a given flight time.

역할 창조를 위한 '몸틀(body schema)' 형성 연구 (A Study on Forming 'Body Schema' for Role Creating)

  • 송효숙
    • 한국연극학
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    • 제52호
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    • pp.319-357
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    • 2014
  • Formation of 'body schema' is the start for actor to create role and becomes the root and the foundation of existing as a role on the stage. For this, an actor needs to form 'scheme of role' with escaping from own 'body schema.' 'Schema of role' is formed by acquiring through synthesizing daily basic actions, namely, walking, standing, sitting, hand stretching, bending, and touching. The body schema, which was made with simple and usual actions, has fundamental significance in a sense of becoming the body in which the past traces in a role are habituated while energy as a role flows. As for the process of forming body schema, an actor first needs to obtain the visualized materials like photo, magazine, picture and image available for seeing a role specifically and clearly based on what analyzed a character. An actor needs to have three-dimensional image available for always recalling it in the head during acting. To do this, image data available for fundamentally capturing routine actions along with body structure are still more useful. Next, the body schema is formed by interaction with environment. Thus, there is a need of passing through the two-time process of forming body schema. Firstly, the body schema is made on routine actions in a role as physical condition of a role in actor's own everyday life. Secondly, the body schema is made on routine actions available for moving efficiently and economically in line with the environment of performance. A theatrical stage is the temporal space of rhythm and rule different from routine space. What forms body schema immediately in the second phase without body schema in the first phase ultimately becomes what exists as actor's own body, not the body of a role. The body schema, which was formed as the second process, is what truly has identity as a role in the ontological aspect, comes to experience the oppositional force in muscle, a qualitative change in energy, and emotional agitation in the physical aspect, and experiences perception, thinking, volition, and even consciousness with the entire body in the cognitive dimension. Thus, the formation of body schema can be known to be just a method of changing even spiritual and emotional layer. Body schema cannot be made if there is no process of embodiment and habit. Embodiment and habit are not simply the repeated, empty and mechanical action in the body. But, habit itself has very important meanings for forming body schema for role creating. First, habit allows the body itself to learn and understand a meaning. Second, habit relies upon environment, thereby allowing an actor of making the habituated body schema to recognize environment. Third, habit makes the mind. The habituated body schema is just the mind and the ego of a person who possesses the body schema. Fourth, habit comes to experience the expansion in energy and the expansion in existence. It may be experienced through interrelation among actor's body, tool, and environment. Fifth, habit makes identity of the body. Hence, this just becomes what secures identity of a role. These implications of habit are the formation of body schema, which is maintained with the body of being remembered firmly through being closely connected with the process of neural adaptation. Finally, it sought for possibility of practice as one method of forming body schema for role creating through Deleuze's '-becoming' theory. As 'actual animal-becoming' is real '-becoming' of forming structural transformation in the physical dimension, it meets with what the formation of body schema pursues actuality and reality. This was explained with a concept as saying of 'all '-becoming' molecular' by Deleuze/Guattari. 'Animal of having imitated animal's characteristic- becoming' is formed by which the body schema relies upon environment. In this way, relationship among the body, tool and environment has influence even upon a change in consciousness, thinking, and emotion, thereby being able to be useful for forming body schema in a sense of possibly experiencing ultimately expansion in role, namely, expansion in existence.

해수순환 방파제를 고려한 폰툰형 구조물의 유탄성응답 해석 (Analysis of Hydroelastic Response of a Pontoon-type Structure Considering Effect of Wave Breaker with Underwater Opening)

  • 홍사영;최윤락;홍석원
    • 대한조선학회논문집
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    • 제40권5호
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    • pp.53-59
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    • 2003
  • Ocean space utilization using VLFS(Very Large Floating Structures) can provide environmental impact free space by allowing sea water flow freely through the floating structure. Use of Pontoon type VLFS for that purpose needs employment of breakwaters for reduction of wave effects. Therefore, in order to maximize advantage of environmental impact free structure, the breakwater should be the one that can allow water flow freely through it, too. In this paper hydroelastic response of a pontoon type structure is analyzed considering breakwaters which allow water flow through its opening at bottom of the breakwaters. Mode superposition technique is used for solving equation of flexible body while interactions between the pontoon and breakwaters is considered based on generalized mode concept. Bi-quadratic nine node higher-order boundary element method is adopted for more accurate numerical treatment near sharp edged body shape. Performance of various combinations of breakwaters is investigated.

Development of a Simulator of a Magnetic Suspension and Balance System

  • Lee, Dong-Kyu;Lee, Jun-Seong;Han, Jae-Hung;Kawamura, Yoshiyuki;Chung, Sang-Joon
    • International Journal of Aeronautical and Space Sciences
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    • 제11권3호
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    • pp.175-183
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    • 2010
  • The increased demand for a higher performing magnetic suspension and balance system (MSBS) resulted in an increase in costs for the efforts necessary for achieving an improved MSBS. Therefore, MSBS performance should be predicted during the design in order to reduce risk. This paper presents the modeling and simulation of an MSBS that controls 6-degree of freedom (DOF) of an aerodynamic body within the MSBS. Permanent magnets and electromagnets were modeled as coils, and this assumption was verified by experimental results. Finally, an MSBS simulator was developed, predicting that the MSBS is able to contain the model within a bounded region as well as measure external forces acting on the body during wind tunnel tests.

요소 기반의 헬리콥터 시뮬레이션 프로그램 개발 (Development of a Component Based Helicopter Simulation Program)

  • 신재화;최기영
    • 한국항공우주학회지
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    • 제35권6호
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    • pp.548-555
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    • 2007
  • 기존의 헬리콥터 모델링은 주로 많은 가정들을 통한 수식 전개에 의존해 왔기 때문에 모델링이 어렵고, 특정 구간에서만 활용 가능하며, 모델링 구성이 바뀌면 많은 수정이 거쳐야 한다는 단점들이 제기되어 왔다. 본 연구에서는 다물체 동역학 기법을 적용한 헬리콥터 시뮬레이션 프로그램을 개발하여 AH-1 헬리콥터에 대한 모델링을 수행하였고, 또한 시뮬레이션 결과를 비행 시험 데이터 및 상용 헬리콥터 시뮬레이션 분석 도구인 FLIGHTLAB과 비교하여 그 가능성을 확인해 보았다.

노인을 위한 유비쿼터스 주거환경 계획요소에 관한 연구 (Ubiquitous Services in Residential Environment for Older Adults)

  • 김형우;권오정
    • 한국주거학회:학술대회논문집
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    • 한국주거학회 2008년 추계학술발표대회 논문집
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    • pp.316-321
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    • 2008
  • As people are aging, there are changes about biological psychological sociological. For these reasons, it will arise that changing body size, decreasing power of body, shrinking of living, becoming dull the senses, and feeling alienation loneliness sense of distance about society. Many studies have been done to give residential space supporting older adults' living. Recently many ubiquitous technologies are being development and applied to residential space. The purpose of this study was to classified ubiquitous services by housing supporting concept and older people's physical, psychological and social characteristics and to identify needs for ubiquitous services by older adults. The researches developed a survey instrument and collected the data from 260 people in July to August, 2008 who were more than 40 years old. The results of this study found that residents' current needs and suggested ubiquitous services in future residential environment for older adults.

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Black Hole Binaries Dynamically Formed in Globular Clusters

  • Park, Dawoo;Kim, Chunglee;Lee, Hyung Mok;Bae, Yeong-Bok;Belczynski, Krzysztof
    • 천문학회보
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    • 제42권1호
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    • pp.43.1-43.1
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    • 2017
  • We investigate properties of black hole (BH) binaries formed in globular clusters, by using direct N-body simulations. Comparing with previous studies which usually considered single BH masses, our models consist of two-component BH masses, or continuous BH mass function with single mass ordinary cluster stars. During the early stage of dynamical evolution, initially distributed BHs are move to the cluster center by dynamical friction, then BH-BH binaries start to be formed, and eventually be ejected from the cluster due to three body interaction. Finally we find the formation efficiency of high mass BHs are alwats larger than that of lower mass BHs, implying that a BH mass spectrum expected from GW observation should be biased to high mass. In addition, mass ratios of BHs in binaries prefer similar masses (ratio~1), while the most extreme case is less than 3. Expected merger rate from our models is about 7 BH-BH mergers per $Mpc^3$ per yr.

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