• Journal of Astronomy and Space Sciences
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• v.25 no.4
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• pp.361-374
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• 2008

Recently, satellite formation flying has been a topic of significant research interest in aerospace society because it provides potential benefits compared to a large spacecraft. Some techniques have been proposed to design optimal formation trajectories minimizing fuel consumption in the process of formation configuration or reconfiguration. In this study, a method is introduced to build fuel-optimal trajectories minimizing a cost function that combines the total fuel consumption of all satellites and assignment of fuel consumption rate for each satellite. This approach is based on collocation and nonlinear programming to solve constraints for collision avoidance and the final configuration. New constraints of nonlinear equality or inequality are derived for final configuration, and nonlinear inequality constraints are established for collision avoidance. The final configuration constraints are that three or more satellites should form a projected circular orbit and make an equilateral polygon in the horizontal plane. Example scenarios, including these constraints and the cost function, are simulated by the method to generate optimal trajectories for the formation configuration and reconfiguration of multiple satellites.

• Smart Structures and Systems
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• v.30 no.3
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• pp.239-243
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• 2022

We investigate the influence of nonlinear viscoelastic damping on the response of a cantilever sensor covered by piezoelectric layers in a symmetric or asymmetric configuration. We formulate an initial-boundary-value problem which consistently incorporates both geometric and material nonlinearities including the effect of viscoelastic damping which cannot be ignored for micro- and nano-mechanical sensor operation in a vacuum environment. We employ an asymptotic multiple-scales methodology to yield the system nonlinear frequency response near its primary resonance and employ a model-based estimation procedure to deduce the system damping backone curve from controlled experiments in vacuum. We discuss the effect of nonlinear damping on sensor applications for scanning probe microscopy.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.742-748
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• 1993

The dynamics and control of two complex column configurations (sidestream column with stripper; prcfractionater/sidestream column configuration), which are multivariable interacting and nonlinear, have been studied. A new control scheme developed by Hanand Park(1993) to deal with the nonlinear and multivariable nature of distillation processes has been applied to these complex distillation configurations. The control scheme incorporates a nonlinear wave model into a generic model control framework. An observer based on the nonlinear wave model is used to determine the profile positions of distillation column sections. The control scheme enables tight control of the profile position of each column section that leads to fast stabilization of product compositions.

• Journal of Astronomy and Space Sciences
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• v.21 no.3
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• pp.209-220
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• 2004

Some methods have been presented to get optimal formation trajectories in the step of configuration or reconfiguration, which subject to constraints of collision avoidance and final configuration. In this study, a method for optimal formation trajectory-planning is introduced in view of fuel/time minimization using parameter optimization technique which has not been applied to optimal trajectory-planning for satellite formation flying. New constraints of nonlinear equality are derived for final configuration and constraints of nonlinear inequality are used for collision avoidance. The final configuration constraints are that three or more satellites should be placed in an equilateral polygon of the circular horizontal plane orbit. Several examples are given to get optimal trajectories based on the parameter optimization problem which subjects to constraints of collision avoidance and final configuration. They show that the introduced method for trajectory-planning is well suited to trajectory design problems of formation flying missions.

• Journal of the Korean Ceramic Society
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• v.34 no.4
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• pp.429-435
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• 1997

The third order nonlinear optical susceptibilities, {{{{ chi }}(3), of the CuCl doped alumino-borosilicate glasses were measured by the two beam configuration DFWM method and the absorption saturation method, and the measured {{{{ chi }}(3) values were about 10-8 esu in both methods. The response time was estimated to be about 105ps from the time decay curve of the luminescence spectra obtained by time-correlated single-photon counting (TCSPC) method.

• Bulletin of the Society of Naval Architects of Korea
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• v.23 no.1
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• pp.3-12
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• 1986

This paper investigates the static configurations and the dynamic behaviors of a single point mooring line. To obtain the static configuration and static tension distribution along the mooring line, including the effect of fluid nonlinear drag and the elasticity of the line, the Runge-Kutta fourth order numerical method was used. The relationship between the horizontal excursion and the horizontal restoring force component of the mooring line, which is very important to a mooring line design, and the effect of a subsurface buoy on the static configuration are presented. In nonlinear dynamic analysis including nonlinear fluid drag acting on the line and geometrical nonlinearity for large deflections, finite element method using updated Lagrangian was used to obtain the solution. In the case of upper end harmonic excitation of the mooring line, the dynamic motion and the tension were also presented.

• Asia Marketing Journal
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• v.18 no.1
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• pp.23-35
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• 2016

Product customization has been popular since Internet shopping began. Many firms have introduced customization configuration systems, allowing customers to choose a wide range of product attributes, attracting them to participate in the shopping process, and increasing customer satisfaction. Paradoxically, the attribute-by-attribute (AbA) choice in the customization process requires a high-information processing load resulting in shopper confusion. To reduce this confusion, the CvSS (customization via starting solution) system has recently been developed. However, this system provides solution support only for the starting point of the configuration process. Thus, in this study, the authors proposes the CvWS (Customization via Waypoint Solutions) system, which would greatly reduce the customer effort needed to complete the configuration process by using a novel approach to solve the nonlinear knapsack problem. The newly proposed system is theoretically compared with the AbA customization as well as the CvSS system. Also, its feasibility is discussed in the context of the nonlinear multiconstraint knapsack problem.

• Journal of the Korean Mathematical Society
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• v.61 no.3
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• pp.565-602
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• 2024

We study the collective behaviors of two second-order nonlinear consensus models with a bonding force, namely the Kuramoto model and the Cucker-Smale model with inter-particle bonding force. The proposed models contain feedback control terms which induce collision avoidance and emergent consensus dynamics in a suitable framework. Through the cooperative interplays between feedback controls, initial state configuration tends to an ordered configuration asymptotically under suitable frameworks which are formulated in terms of system parameters and initial configurations. For a two-particle system on the real line, we show that the relative state tends to the preassigned value asymptotically, and we also provide several numerical examples to analyze the possible nonlinear dynamics of the proposed models, and compare them with analytical results.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.292-299
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• 1999

In order to investigate dynamic behaviors of marine cables under wave and earthquake forces a geometric nonlinear. F, E formulation of marine cables is presented and tangent stiffness and mass matrices for the isoparametric cable element are derived, The initial equilibrium state of cables subjected to self -weights and current forces is determined and free vibration and dynamic nonlinear analysis of cable structures under additional environmental loads are performed based on the initial configuration Challenging examples are presented and discussed in order to demonstrate the feasibility of the present finite element method and investigate dynamic nonlinear behaviors of marine cables.

• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1131-1136
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• 2008

The electrical repulsive energy between two model cylinders was calculated by solving nonlinear Poission- Boltzmann (P-B) equation under Derjaguin approximation. Effects of the surface potential, Debye screening length, and configuration of cylinders on the repulsive interaction energy were examined. Due to the anisotropy of the shape of cylinder, the interaction repulsive energy showed dependence to the configuration of particles; cylinders aligned in end-to-end configuration showed largest repulsive energy and crossed particles had lowest interaction energy. The configuration effect is originated from the curvature effect of the interacting surfaces. The curved surfaces showed less repulsive energy than flat surfaces at the same interacting surface area. The configuration dependency of interaction energy agreed with the previous analytical solution obtained under the linearized P-B equation. The approach and results present in this report would be applicable in predicting colloidal behavior of cylindrical particles.