• The Journal of Korea Robotics Society
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• v.6 no.4
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• pp.317-322
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• 2011

An augmented state feedback controller for a Wheeled Inverted Pendulum (WIP) is proposed in this research. The augmented state feedback controller is able to keep the WIP returning to the origin. Generally, the WIP has both stable and unstable equilibrium points. To keep the WIP over the unstable equilibrium point, the WIP consistently is being controlled. A simple state feedback controller is letting the WIP out of the origin when the center of gravity of the WIP locates out of the schematic center line. In some case of applications, it may not be desirable that the WIP is drifting out of the initial location. The proposed augmented state feedback controller is able to keep the WIP at the initial location whether its center of gravity lies out of the center line or not. Numerical simulations are carried out to show the validation of the augmented sated feedback controller.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.71-76
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• 2001

An electret filter is composed of permanently charged electet fibers and is widely used in applications requiring high collection efficiency and low-pressure drop. In this work, the collection efficiency of the filter media used in manufacturing cabin air filters was investigated by using poly-disperse particles when submicron particles are loaded. Long-term experiments were conducted by applying different charging states, which are spray electrification and charge equilibrium by bipolar ionization. In order to investigate on the effect of particle loading in filter media, NaCl particles were generated from 0.1% and 1% solutions by an atomizer. In NaCl 0.1%, the collection efficiency of electret filter decreased and then did not change in equilibrium state. In the case of relative larger particles of NaCl 1%, collection efficiency for the equilibrium charged particles increases due to the particle loading on the filter fibers. Particles charged by spray electrification are small in collection efficiency after equilibrium state and increase of filter media's pressure drop was very low in comparison of the equilibrium charged particles.

• Journal of Korean Public Health Nursing
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• v.26 no.3
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• pp.428-439
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• 2012

Purpose: The purpose of this study was to define and clarify the concept of 'equilibrium' in community-dwelling elderly persons with chronic diseases. Methods: A hybrid model was used for development of the concept of equilibrium. The model included a field study conducted in Seoul, Korea. Participants in this study included 12 elderly persons with chronic diseases who were taking medicine regularly. Results: The concept of equilibrium was found to be a complex phenomenon having meaning in two dimensions: the family-friendly and social relation-oriented dimensions. Four attributes and nine indicators were defined. Conclusion: Equilibrium was defined as the state of having health recognition, will power, and motive power (family-friendly dimension) and having a feeling of participation (social relation-oriented). Therefore, nurses who work with elderly persons with chronic disease in the community should be aware of the attributes and indicators of equilibrium in order to enhance the equilibrium of their elderly clients with chronic diseases.

• Journal of applied mathematics & informatics
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• v.29 no.5_6
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• pp.1327-1335
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• 2011

This paper demonstrates that there is a unique exponentially stable equilibrium state of a class of impulsive cellular neural network with delays. The analysis exploits M-matrix theory and generalized comparison principle to derive some easily verifiable sufficient conditions for the global exponential stability of the equilibrium state. The results extend and improve earlier publications. An example with its simulation is given for illustration of theoretical results.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.206-210
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• 2004

This paper proposes a new training system for equilibrium sense using unstable platform. This training system for equilibrium sense consists of an unstable platform, a computer interface circuit and software program. Postural instability changes the weighting of different types of sensory information and the state of the equilibrium maintenance system. In order to improve the equilibrium sense, we developed software program such as a block game, sine curve training (SCT) and pingpong game using Visual C++. Using this system and training programs, we performed an experiment to train the equilibrium sense of a subject. To evaluate the effects of balance training, the time maintained on the target and the moving time to the target are measured. As a result, the moving time to the target and time to maintain cursor on the target improved through repeating equilibrium sense training. It was concluded that this system was reliable in the evaluation of equilibrium sense. We expect that this system might be applied to clinical use as an effective balance training system.

• Journal of Korean Society of Steel Construction
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• v.14 no.4
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• pp.539-547
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• 2002

The study proposed the initial equilibrium state analysis method that considers axial deformation, in order to accurately determine the initial shape of a cable-stayed bridge. Sepecifically, the proposed method adopted the successive iteration method. In order to evaluate appropriate initial cable force introduced in the initial equilibrium state analysis, parametric studies were performed and a useful linear analysis method proposed. The geometrically nonlinear static behaviors of cable-stayed bridges were considered, using three-dimensional frame element and elastic catenary cable element. The usefulness and applicability of the analytic method proposed in this study were demonstrated using numerical examples, including a real cable-stayed bridge. The algorithm, is applicable in cases wherein axial deformation is not adopted in the fabrication camber, or final cable force is adjusted to eliminate construction and fabrication errors occurring during construction.

• Ocean and Polar Research
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• v.42 no.1
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• pp.77-88
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• 2020

This paper presents the coordinate systems used for trawl doors modeling, and provides matrix equations of connection between these systems. The projections of the forces acting on the door into axes of various coordinate systems were obtained, which were used in the door equilibrium equations. Six equilibrium conditions for the door as a solid were obtained: formulas that allow for the door area in plan to be determined; its weight in water; its mass; three moment equations for determining the position of the warp and backstrops fastening points to the door with triangular and quadrangular backstrop arrangements. It was found that the moment equilibrium equations of trawl doors are generally incompatible, which was not found by any of the authors who have previously conducted research into trawl doors. Using the Kronecker-Capelli theorem, the compatibility equation is obtained. This equation includes the coordinates of the backstrop fastening points to the door, which means that these points cannot be randomly selected. The technique of determining the warp and backstrops' fastening points position to the door is described. Conditions of directional (by angle of attack) and roll (in angle of roll) stability of the doors' equilibrium are presented. The equations presented in this paper comprise a mathematical model that allows, when designing the doors, to select optimal parameters, as well as to carry out adjustments for trawling purposes to ensure the stable movement of the doors and the entire trawl system.

• ETRI Journal
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• v.31 no.1
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• pp.89-91
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• 2009

This letter considers the problem of resource sharing among a relay and multiple user nodes in cooperative transmission networks. We formulate this problem as a sellers' market competition and use a noncooperative game to jointly consider the benefits of the relay and the users. We also develop a distributed algorithm to search the Nash equilibrium, the solution of the game. The convergence of the proposed algorithm is analyzed. Simulation results demonstrate that the proposed game can stimulate cooperative diversity among the selfish user nodes and coordinate resource allocation among the user nodes effectively.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.6
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• pp.1000-1006
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• 2007

This paper presents a methodology to calculate an optimal solution of equilibrium to differential algebraic equations for power systems. It employs a nonlinear interior point method to solve the optimization formulation which includes dynamic equations representing the two-axis synchronous generator model with AVR and speed governing controls, algebraic equations, and steady-state nonlinear loads. This paper also adopts two algorithms for the improvement of solution convergence. In power system analysis and control, equilibrium optimization (EOPT) is applicable for diverse purposes that need the consideration of dynamic model characteristics at a steady-state condition.

• Textile Coloration and Finishing
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• v.10 no.3
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• pp.36-42
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• 1998

The dyeabilities of C.I. Reactive Blue 19(B19, MW ; 626), C.I. Reactive Blue 4(B4, MW ; 637) and C.I. Reactive Black 5(B5, MW : 991) were investigated. Initial dyeing rates were increased and the amount of dye on the fabric at equilibrium was decreased with temperature like other ordinary dyeing processes. Activation entropy$(\Delta{S}^*)$ was decreased because of loose bonding between dyestuffes and fiber molecules at transition state. It can be clarified that the entire reaction is exothermic and the number of molecular species at transition state becomes greater from decrease in activation enthalpy$(\Delta{H}^*)$ and the increase in activation free energy$(\Delta{G}^*)$ with temperature, respectively. The amount of B19 on the fabric at equilibrium was greater than that of B4, because B4 became unreactive towards textile substrates through hydrolysis. Due to the biggest size of the dye molecule, the reaction rate of B5 was the slowest but its difunctional group played an important role in achieving the greatest amount of dye on the fabric at equilibrium.