• Title/Summary/Keyword: Encounter force

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Wave Exciting Forces Acting on Ships in Following Seas (추파중(追波中)에서 항행(航行)하는 선체(船體)에 작용(作用)하는 파강제력(波强制力)에 관(關)한 연구(硏究))

  • Kyoung-Ho,Son;Jin-Ahn,Kim
    • Bulletin of the Society of Naval Architects of Korea
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    • v.21 no.3
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    • pp.27-34
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    • 1984
  • When a ship is travelling in following seas, the encounter frequency is reduced to be very low. In that case broaching phenomenon is most likely to occur, and it may be due to wave exciting forces acting on ships. It is thought that the wave exciting forces acting on ships in following seas almost consist of two components. One is hydrostatic force due to Froude-Krylov hypothesis, and the other is hydrodynamic lift force due to orbital motion of water particles below the wave surface. In the present paper, the emphasis is laid upon wave exciting sway force, yaw moment and roll moment acting on ships in following seas. The authers take the case that the component of ship speed in the direction of wave propagation is equal to the wave celerity, i.e., the encounter frequency is zero. Hydrostatic force components are calculated by line integral method on Lewis form plane, and hydrodynamic lift components are calculated by lifting surface theory. Furthermore captive model tests are carried out in regular following waves generated by means of a wave making board. Through the comparison between calculated and measured values, it is confirmed that the wave exciting forces acting on ships in following seas can be predicted in terms of present method to a certain extent.

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A Fundamental Study on the Transverse Stability of Ships in Following Seas (추파중에서 항행하는 선박의 복원성능에 관한 기초적 연구)

  • 윤진동;손경호
    • Journal of the Korean Institute of Navigation
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    • v.11 no.2
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    • pp.61-72
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    • 1987
  • When a ship is running in following seas, the encounter frequency is reduced to a very low one. In that case broaching, surfiding and capsizing phenomena are most likely to occur due to wave exciting forces acting on a ship in following seas. In this paper, the emphasis is mainly laid upon transverse stability of ships following seas, which is related to capszing phenomenon. The authors take the case that ship speed is equal to the wave celerity, i.e., the encounter frequency is zero. Hydrostatic force and moment due to Froude-Krylov hypothesis are calculated by line intergral method. Transverse stability is evaluated from hydrostatic force and moment. Through the application of present calculation method to box-shaped vessel, it is confirmed that the transversestability of a vessel can be reduced to critical level at wave crest.

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Accumulation and Decay of Macroscopic Correlations in Elementary Reactions Kinetics

  • Doktorov, Alexander B.;Kipriyanov, Alexander A.;Kipriyanov, Alexey A.
    • Bulletin of the Korean Chemical Society
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    • v.33 no.3
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    • pp.941-952
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    • 2012
  • In the present contribution the Encounter Theory (ET) (the prototype of the classical Collision Theory in rarefied gases) concepts for widely occurring diffusion assisted irreversible bulk reactions A + A ${\rightarrow}$ C and A + B ${\rightarrow}$ C in liquid solutions examined by the authors in the literature are analyzed and compared with each other for these different types of reactions. It is shown that for a particular case of equal initial concentrations $[A]_0=[B]_0$ in the reaction A + B ${\rightarrow}$ C, when the kinetics of both reactions A + A ${\rightarrow}$ C and A + B ${\rightarrow}$ C in the framework of formal chemical kinetics and ET are the same, the accumulation of macroscopic correlations breaking the concepts of independent encounters and leading to the Generalized Encounter Theory (GET) are drastically different. The influence of the force interaction and the decay of nonstable reactants on the time behavior the macroscopic correlations is also briefly discussed.

A Force Reflecting Control for Telemanipulators with Control Input Saturation (제어입력 포화를 가지는 원격조작기의 힘반영 제어)

  • Ahn, Sung-Ho;Yoon, Ji-Sup;Lee, Sang-Jeong
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.49 no.10
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    • pp.572-581
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    • 2000
  • When the manipulator consisting of high ratio gear reducers at its joints is used as the slave manipulator in teleoperated systems, its dynamic characteristics is much slower than that of the master manipulator and it is likely to encounter the saturation in the input magnitude. The control input saturation generates an windup phenomenon that the system stability and position tracking performance of the slave manipulator are to be deteriorated. This paper proposes an force reflecting control scheme and its design method which compensates the control input saturation with absolute stability. The proposed scheme is shown to give a stable force reflection while compensating for control input saturation effectively.

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A Study on the Safety of Anchoring for Ulsan M-10 Anchorage (울산항 M-10 정박지의 정박안전성 연구)

  • KIM, Se-Won
    • Journal of Fisheries and Marine Sciences Education
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    • v.21 no.2
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    • pp.291-305
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    • 2009
  • As you known well, Ulsan port is very famous for handling chemical products which occupies about 80% of quantities of all Korean ports. Many ship's operators prefer to handle liquid cargo es at proper anchorages instead of the berth for saving port expenses. Ulsan M-10 anchorage was assigned for handling liquid cargoes, however this anchorage's space is restricted by the oil pipeline which lays under seabed about 400m off from the center of M-10 anchorage, for which we have to consider of the external force and counter force for keeping the safety of anchoring. Where, external force is induced by wind, tidal currents and wave while counter force is induced by holding power of anchor/chain. In this study, author evaluated a method to analyze theoretically the limit of external force condition up to which an anchoring ship can keep her position without dragging, and for which applied to many kinds of combined Ships as mother ship of 50,000 DWT Tanker and 4 sizes of Tanker as alongsided ship.

A Study on Non-representation Approach Indicated in Paintings and Architecture - Focus on Francis Bacon's paintings and SANAA's Architectural projects - (회화와 건축에서 나타나는 비재현적 접근방법에 관한 연구 - 프란시스 베이컨의 회화와 SANAA의 건축 프로젝트를 중심으로 -)

  • Park, So-La;Lee, Young-Su
    • Korean Institute of Interior Design Journal
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    • v.21 no.5
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    • pp.114-121
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    • 2012
  • Gilles Deleuze is a philosopher who replaces the world of representation defined as supremacy of identity with the contemporary reason of non-representation in the history of western philosophy that wants to transcend Plato. Deleuze developed his own philosophical concept through philosophical reason and encounter with arts, for which reason he exerted a great influence on artists and architects in diverse fields. Particularly, 'Logic of Sensation' published in 1981 considers the non-representation painting approach through Francis Bacon's painting theory defined as 'invisible force's visibility'. And it is considered that SANAA's architecture among many contemporary architects accepted the essence of Deleuze's philosophy and continuously reflects it on projects. Hence, objective of the present study is to consider how the non-representation constituting a root for Deleuze's reason has been indicated in paintings and architecture through examining the works by Bacon and SANAA. First, a theoretical consideration will be directed to non-representation, followed by an analysis of Bacon's painting works and SANAA's architecture projects from the viewpoints of the force of isolation, the force of transformation, the force of dissipation and the force of time dealt with by Deleuze in 'Logic of Sensation'. Finally, through such analysis, the characteristics of Deleuze's non-representation indicated in architecture and paintings will be derived.

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Macromolecular Cytosolic Delivery: Cell Membranes as the Primary Obstacle

  • Larson, Gretchen M.;Lee, Kyung-Dall
    • Archives of Pharmacal Research
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    • v.21 no.6
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    • pp.621-628
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    • 1998
  • The "evolution" of a thing, a custom, an organ is thus by no means its progressus toward a goal, even less a logical progressus by the shortest route and with the least expendit ure of force, but a succession of more or less profound, mutually independent processes of subduing, plus the resistances they encounter, the attempts at transformation for the purpose of defense and reaction, and the results of successful counteractions. The form is fluid, but the "meaning" is even more so (Friedrich W. Nietzsche).

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A Study on the Simplified Prediction Method of Air Resistance for Towing Force Calculation of Disabled Ships (사고선박 예인력 계산을 위한 공기저항 간편 추정법 연구)

  • Kim, Eun-Chan;Choi, Hyuek-Jin
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.17 no.3
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    • pp.198-204
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    • 2014
  • Ships sailing the seas encounter air resistance. The air resistance depends on the shape of the above-water hull, the ship speed, the wind speed and wind direction. The experimental or statistical methods which are used to predict the air resistance are one of the essential procedures of the calculation of the towing force of the disabled ships. This paper shows simplified air resistance prediction method using the variables of the projected area of the above-water hull, the speed of the ship, the wind speed and its direction. These methods have been applied to the existing computer program which had been set up to predict the towing force of the disabled ships.

Force Reflecting Position Control for 2 Axes Heavy-Duty Power Manipulators (2축 고하중 조작기의 힘반영 위치제어)

  • Ahn, Sung-Ho;Park, Byung-Suk;Yoon, Ji-Sup;Koh, Youn-Se;Lee, Sang-Jeong
    • Proceedings of the KIEE Conference
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    • 2000.07d
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    • pp.2910-2912
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    • 2000
  • Since the heavy-duty power manipulator has high ratio gear reducers at its joints, its dynamic characteristics are much slower than that of the master manipulator and it is likely to encounter the saturation in the input magnitude when it is used as the slave manipulator in telemanipulator systems. This paper proposes a force reflecting position control scheme for 2 axes heavy-duty power manipulator which compensates control input saturation. A series of experiments is shown to give an excellent tracking performance regardless of saturation.

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Analysis on motions characteristics of Floaters using two-dimensional Boundary Element Method (2차원 경계요소법을 이용한 부유체의 운동 특성 연구)

  • Baek, Mi-Seon;Seong, Yu-Chang
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2013.06a
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    • pp.136-138
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    • 2013
  • Current, standards light buoys as maritime traffic safety facilities have 10 different types of buoys and the smallest size of those is 4.4m. Therefore, making for easy replacement and repair parts for the type of small light buoys is proposed. Meanwhile, position reliability of floaters by external forces in the environment fall and stability examination should be considered for prohibiting accidents as loss. In this paper, a new light buoy is analyzed on Encounter Frequency types using commercial program and fluid forces is simulated on cross-sectional shape of the float using two-dimensional Boundary Element Method(BEM).

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