• Title/Summary/Keyword: forces

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Role of extrinsic physical cues in cancer progression

  • Ok-Hyeon Kim;Tae Jin Jeon;Yong Kyoo Shin;Hyun Jung Lee
    • BMB Reports
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    • v.56 no.5
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    • pp.287-295
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    • 2023
  • The tumor microenvironment (TME) is a complex system composed of many cell types and an extracellular matrix (ECM). During tumorigenesis, cancer cells constantly interact with cellular components, biochemical cues, and the ECM in the TME, all of which make the environment favorable for cancer growth. Emerging evidence has revealed the importance of substrate elasticity and biomechanical forces in tumor progression and metastasis. However, the mechanisms underlying the cell response to mechanical signals-such as extrinsic mechanical forces and forces generated within the TME-are still relatively unknown. Moreover, having a deeper understanding of the mechanisms by which cancer cells sense mechanical forces and transmit signals to the cytoplasm would substantially help develop effective strategies for cancer treatment. This review provides an overview of biomechanical forces in the TME and the intracellular signaling pathways activated by mechanical cues as well as highlights the role of mechanotransductive pathways through mechanosensors that detect the altering biomechanical forces in the TME.

A scheme on strengthening of R.O.K reserved force (예비전력 정예화 방안)

  • Kim, Jae-Sam
    • Journal of National Security and Military Science
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    • s.5
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    • pp.1-45
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    • 2007
  • Reserved forces of ROKA are in charge of replacement of TOE in the wartime and mission of rear area operation. But there is institutional inertia in the law and organization oriented to fill human resources rather than take mission. We need to prepare for the investment and arrangement of reserved forces as military power that would be replaced standing forces. In this portion, to reinforce reserve forces elite, First, efficient mobilization regulations and systems are suggested. I covered a maintenance of relevant mobilization ordinances which need to legislated and approved by national assembly for wartime and development of mobilization system which might lose the appropriate time for mobilization due to complicated declaration procedures and measures to overcome the panic at the initial stage of the war and organization and employment of nationwide transportation system and mobilization center. To ensure efficient resource management and mobilization of reserve forces with a number of approximately 3 million, there's a necessity of organization for integration and conciliation. To make it real, I suggested establishing and employing the mobilization center, on first phase, employ the mobilization center focusing on homeland divisions, on second phase, it is advisable to convert to national level mobilization system and develop to central mobilization center focusing on national emergency planning committee. During peacetime, in conjunction with Mobilization Cell, mobilization center can conduct resource survey and integrate and manage mobilization resources and take charge of mobilization training of subordinate units, and during wartime, in conjunction with mobilization coordination team and Cell, can ensure the execution of mobilization. Second, Future oriented reserve forces management system such as service system of reserve forces and support system of homeland defense operations. Current service and trainings of reserve forces by the year have very low connection, as it is very complex to manage the resources and trainings, and service and training lack the equity, re-establishment of service system is required. Also in an aspect of CSS and cultivation support for reserve forces, as the scope and limitation of responsibility between the armed forces and autonomous organization is obscure, conditions to conduct actual-fighting exercises are limited. Concentrated budgetting is extremely difficult because reserve forces training fields are scattered nationwide, and facilities and equipments are rapidly getting older. To improve all these, I suggest the organization of homeland defense battalion with a unit of "City-Gun-District" and supporting the local reserve forces. Conduct unit replacement or personal replacement for those who have finished their 1 or 2 years and homeland defense operation duty for those with 3-5 years for consistency and simplification. Third, I suggest Future oriented Reserved Training(FRT) and Training Center oriented training management to establish a reliable reserve training. Reserves carry out expansion of unit, conventional combat mission, homeland defense and logistics support during wartime, and actual-fighting exercise, and disaster relief, peace keeping activities. Despite diverse activities and roles, their training condition still stays definitely poor. For these reasons, Modernization of weapons and facilities through gradual replacement and procurement is essential to enhance mobilization support system.

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A Study on the Steady Drift Forces on Barge (바아지선에 작용하는 정상표류력에 관한 연구)

  • 조효제
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.33 no.1
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    • pp.38-45
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    • 1997
  • The steady drift forces on a barge in waves are investigated. The steady drift forces due to a near-field method which is based on direct integration of the pressure acting on the submerged surface of barge are compared with those due to far-field method which is based on the theory of momentum conservation. Numerical results of the linear motions are compared with the experimental and numercal ones which was submitted in the literature. A convergence of the steady drift forces according to the increase of the number of panels which represent the submerged surface are discussed.

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Real-time obstacle avoidance for mobile robot (이동 로봇을 위한 실시간 충돌 회피)

  • 범희락;조형석
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.658-662
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    • 1991
  • In this paper, a real-time obstacle avoidance for mobile robot based on the readings of the ultrasonic sensors is presented. The twenty eight ultrasonic sensors are arranged in ring and controlled by microprocessor. The readings of the ultrasonic sensor is converted into the virtual forces called repulsive forces, which are the elastic and damping forces. Then, the direction and speed of mobile robot in the cluttered environment are determined by the virtual forces. The effectiveness of the proposed method is verified from a series of simulation studies.

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An Experimental Study on the Restraining Characteristics through Square Drawbead (사각형 드로오비드 인출 특성에 관한 실험적 연구)

  • 박원배;김창만;전기찬;서대교
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1995.03a
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    • pp.170-177
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    • 1995
  • The restraining characteristics for the single square drawbead are discussed. The drawbead restraining forces adn maximum strains by the various drawing angles are measured experimentally. During this procedure , the drawing angles are varied from 0$^{\circ}C$ to 60$^{\circ}C$. Also, the wide range of experimental data of the drawing forces and maximum strains for the various drawbead dimensions, dimensions, clearances and blank holding forces are preseted.

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Crank Angles Design to Reduce the Excitation Forces in 4-stroke Diesel Engine (4행정 기관의 기진력 감소를 위한 크랭크 각 설계)

  • 서영수;박정근;정의봉
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2000.11a
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    • pp.108-114
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    • 2000
  • The excitation forces from the periodical firing pressure in cylinder and the rotating crank mechanism cause lots of vibration problems in diesel engine. In this paper, the theoretical formulas for excitation forces are introduced and computational program for the optimization of crank angle is also developed to reduce the free moments in diesel engine. The computational results of 4-stroke in-line engine are applied to verify the reliability of the program.

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Analysis of Electromagnetic Repulse Forces of MCCB (배선용 차단기의 전자 반발력에 관한 연구)

  • 김길수;임기조;강성화;조현길
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.593-596
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    • 2001
  • It is necessary for calculation of repulsion forces acting on the closed electric contacts flowing over-current, e.g. inrush current and overload currents, to do optimum design of switching devices. In this paper, the farces and flux densities generated by currents at the contact point when circuit breakers are in closed state are obtained by using 3D finite element methode. To be convinced of the results, we measure electrogmanetic repulsion forces on contacts by measuring voltage between opened contacts in MCCB.

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Uncertainty Analysis of Wave Forces on Upright Sections of Composite Breakwaters (혼성제 직립벽에 작용하는 파력의 불확실성 해석)

  • Lee, Cheol-Eung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.23 no.3
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    • pp.258-264
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    • 2011
  • A MCS technique is represented to stochastically analyze the uncertainties of wave forces exerted on the upright sections of composite breakwaters. A stochastical models for horizontal and uplift wave forces can be straightforwardly formulated as a function of the probabilistic characteristics of maximum wave height. Under the assumption of wave forces followed by extreme distribution, the behaviors of relative wave forces to Goda's wave forces are studied by the MCS technique. Double-truncated normal distribution is applied to take the effects of uncertainties of scale and shape parameters of extreme distribution into account properly. Averages and variances of relative wave forces are quantitatively calculated with respect to the exceedance probabilities of maximum design wave height. It is found that the averages of relative wave forces may be decreased consistently with the increases of the exceedance probabilities. In particular, the averages on uplift wave force are evaluated slightly larger than those on horizontal wave force, but the variations of coefficient of the former are adversely smaller than those of the latter. It means that the uncertainties of uplift wave forces are smaller than those of horizontal wave forces in the same condition of the exceedance probabilities. Therefore, the present results could be useful to the reliability based-design method that require the statistical properties about the uncertainties of wave forces.

Prediction of the Spinal Load during Static Loading Conditions using EMG model and Three Optimization models (정적 부하 작업에서 EMG 모델과 세가지 최적화 모델을 이용한 척추 부하 평가)

  • Song, Young Woong;Chung, Min Keun
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.15 no.1
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    • pp.61-70
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    • 2005
  • This study investigated the spinal loads(L5/S1 disc compression and shear forces) predicted from four biomechanical models: one EMG model and three optimization models. Three objective functions used in the optimization models were to miminize 1) the cubed muscle forces : MF3, 2) the cubed muscle stress : MS3, 3) maximum muscle intensity : MI. Twelve healthy male subjects participated in the isometric voluntary exertion tests to six directions : flexion/extension, left/right lateral bending, clockwise/ counterclockwise twist. EMG signals were measured from ten trunk muscles and spinal loads were assessed at 10, 20, 30, 40, 50, 60, 70, 80, 90%MVE(maximum voluntary exertion) in each direction. Three optimization models predicted lower L5/S1 disc compression forces than the EMG model, on average, by 31%(MF3), 27%(MS3), 8%(MI). Especially, in twist and extension, the differences were relatively large. Anterior-posterior shear forces predicted from optimization models were lower, on average, by 27%(MF3), 21%(MS3), 9%(MI) than by the EMG model, especially in flexion(MF3 : 45%, MS3 : 40%, MI : 35%). Lateral shear forces were predicted far less than anterior-posterior shear forces(total average = 124 N), and the optimization models predicted larger values than the EMG model on average. These results indicated that the optimization models could underestimate compression forces during twisting and extension, and anterior-posterior shear forces during flexion. Thus, future research should address the antagonistic coactivation, one major reason of the difference between optimization models and the EMG model, in the optimization models.

A Research on the Classified Structural System in Long-Span Structures (대공간 구조형식 분류체계에 관한 연구)

  • Yang, Jae-Hyuk
    • Journal of Korean Association for Spatial Structures
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    • v.2 no.3 s.5
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    • pp.81-92
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    • 2002
  • The objective of this paper is to help to make decision of the appropriate structural types in long span structured building due to range of span. For the intention, based on 7 forces of structural element, it is analized the relationships among 6 configurations of structural element(d/1), 25 structural types, 4 materials, and span-length known with 186 sample from 1850 to 1996. 1) bending forces: $club(1/100{\sim}1/10),\;plate(1/100{\sim}1/10),\;rahmen(steel,\;10{\sim}24m)\;simple\;beam(PC,\;10{\sim}35m)$ 2) shearing forces: $shell(1/100{\sim}1/1000)\;hyperbolic\;paraboloids(RC,25{\sim}97m)$ 3) shearing+bending forces: plate, folded $plate(RC21{\sim}59m)$ 4) compression axial forces: club, $arch(RC,\;32{\sim}65m)$ 5) compression+tension forces: shell, braced dome $shell(RC,\;40{\sim}201m),\;vault\;shell(RC,\;16{\sim}103m)$ 6) compression+tension axial forces: $rod(1/1000{\sim}1/100)$, cable(below 1/1000)+rod, coble+rod+membrane(below 1/1000), planar $truss(steel,\;31{\sim}134m),\;arch\;truss(31{\sim}135m),\;horizontal\;spaceframe(29{\sim}10\;8m),\;portal\;frame(39{\sim}55m),\;domical\;space\;truss(44{\sim}222m),\;framed\;\;membrane(45{\sim}110m),\;hybrid\;\;membrane\;(42{\sim}256m)$ 7) tension forces: cable, membrane, $suspension(60{\sim}150m),\;cable\;\;beam(40{\sim}130m),\;tensile\;membrane(42{\sim}136m),\;cable\;-slayed(25{\sim}90m),\;suspension\;membrane(24{\sim}97m),\;single\;layer\;pneumatic\;structure(45{\sim}231m),\;double\;layer\;pneumatic\;structures(30{\sim}44m)$

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