• Management Science and Financial Engineering
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• v.19 no.1
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• pp.11-16
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• 2013

This paper derives an equilibrium asset price when there exist three kinds of traders in financial market: a risk-averse informed trader, noise traders, and risk neutral market makers. This paper is an extended version of Kyle's (1985, Econometrica) continuous time model by introducing insider's risk aversion. We obtain not only the equilibrium asset pricing and market depth parameter but also insider's value function and optimal insider's trading strategy explicitly. The comparative static shows that the market depth (the reciprocal of market pressure) increases with time and volatility of noise traders' trading.

• Journal of Biomedical Engineering Research
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• v.13 no.3
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• pp.235-244
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• 1992

In this paper, fluttering behavior of mechanical monoleaflet tilting disc heart valve prostheses during the opening phase was analyzed taking into consideration the impact between the occluder and the guiding strut at the fully open position. The motion of the valve occluder was modeled as a rotating system, and equations were derived by employing the moment equilibrium principle. Forces due to lift, drag, gravity and buoyancy were considered as external forces acting on the occluder. The 4th order Runge-Kutta method was used to solve the governing equations. The results iimonstrated that the occludes reaches steady equilibrium position only after damped vibration. Fluttering frequency varies as a function of time after opening and is in the range of 8-84 Hz. Valve opening appears to be affected by the orientation of the valve relative to gravitational force. The opening velocities are in the range of 0.65-1.42m/sec and the dynamic loads by impact of the occludes and the strut are in the range of 90-190 N.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.10
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• pp.1048-1053
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• 2009

It proposes an simple and intuitive method that calculates the equilibrium pressures of a propellant tank by appling the mass conservation principle on the helium in the liquid propellant and in an ullage volume of the propellant tank. A propellant loading analysis program is developed and validated against the existing reference data. And it has applied to the present developing program, COMS Chemical Propulsion Subsystem and the results are compared, it may use to develop a technology of the next geostationary complex satellite's propulsion system.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.2
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• pp.287-295
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• 1987

The general equation of equilibrium is presented for a stiffened plate on which the stiffeners having rectangular cross-sections are attached by one or both sides with arbitrarily angles. The principle of minimum potential energy is applied using the concept of adjusted-centroid to derive the equilibrium equation for the stiffened plate. Equivalent rigidities in the present theory are in good agreement with the experiments by the vibration method.

• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.4
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• pp.19-35
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• 2007

This study is for detecting the Braess Paradox by stable dynamics in general transportation networks. Stable dynamics, suggested by Nesterov and de Palma[18], is a new model which describes and provides a stable state of congestion in urban transportation networks. In comparison with user equilibrium model based on link latency function in analyzing transportation networks, stable dynamics requires few parameters and is coincident with intuitions and observations on the congestion. Therefore it is expected to be an useful analysis tool for transportation planners. The phenomenon that increasing capacity of a network, for example creating new links, may decrease its performance is called Braess Paradox. It has been studied intensively under user equilibrium model with link latency function since Braess[5] demonstrated a paradoxical example. However it is an open problem to detect the Braess Paradox under stable dynamics. In this study, we suggest a method to detect the Paradox in general networks under stable dynamics. In our model, we decide whether Braess Paradox will occur in a given network. We also find Braess links or Braess crosses if a network permits the paradox. We also show an example how to apply it in a network.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.4
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• pp.381-387
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• 2016

In this paper, the methodology applied to the improvement of stress analyses is extended to free vibration and buckling analyses. The essence of the methodology is the Saint-Venant's principle that is applicable to beam and plate models. The principle allows one to dimensionally reduce three-dimensional elasticity problems. Thus the methodology can be employed to vibration and buckling as well as stress analysis. First, the principle is briefly revisited, and then the formations of classical beam theories are presented. To improve the predictions, the perturbed terms (unknowns) are introduced together with the warping functions that are calculated by stress equilibrium equations. The unknowns are then calculated by applying the equivalence of stress resultants (i.e., Saint-Venant's principle). As numerical examples, cantilever and simply supported beams are analytically solved. The results obtained are compared with those of the classical beam theories. It is shown that the methodology can be used to improve the predictions without introducing shear correction factors.

• Journal of Sasang Constitutional Medicine
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• v.21 no.2
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• pp.11-26
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• 2009

1. Objectives : This research was purposed to reconsider the Dong-Mu's Theory of Nature and Mind(生情論). 2. Methods : The Dong-Mu's interpretation on the first chapter of "The Doctrine of Mean(中庸)", and the related contents of Nature and Emotion(性情) in his literature such as "Gyukchigo(格致藁)", "Donguisusebowon-Sasang chobongyun(東醫壽世保元四象草本卷)" and "Donguisusebowon(東醫壽世保元)" were reviewed. 3. Results and Conclusions : 1. Dong-Mu reinterpreted the concepts about 'Providence(天命) and Human Nature(人性)', 'Not-yet-intentional state(未發) and Intentional state(已發)', 'Nature and Mind(性情)' and 'Equilibrium and Harmony(中和)' in "The Doctrine of Mean", and used these concepts as logical tools in explanation of his thoughts of Human being and medical theory. 2. The generating principle of Nature and Mind(性情) presented as sorrow, anger, joy and pleasure is 'the Principle of Human nature(性理)', which is embodied as 'the Principle of Organ(臟理)' in "Donguisusebowon". The Principle of Organ(臟理) is originated from Heart and lie at lung, spleen, liver and kidney as the form of Four Virtue(四德). 3. The Principle of Organ(臟理) has the position of superintendence and is the generating principle of Nature and Emotion(性情), by which the structural and functional variations between different constitutional types are formed. 4. Dong-Mu's newly established concept of Nature and Emotion(性情) is the core logic in his idea of physiology, pathology and self-cultivation.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.565-573
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• 2004

This study is to present explicit analytical expressions for calculating bearing capacity factor $N_{\gamma}$, to provide results of the numerical computation instead of the graphical method. In this study, $N_{\gamma}$ is proposed in the critical failure surface on assumption that the center of log spiral in the radial shear zone can be located at the any points of around footing. The critical failure surface is one which yields minimum passive pressure $P_{\gamma}$ on the radial shear zone from the family of log spirals accoding to change of the center of log spiral. This study adoptes Terzaghi's bearing capacity principle(e.g., Prandtl's mechanism, limit equilibrium equation, superposition principle) but the soil wedge in an elastic zone makes angle $45^{\circ}+{\phi}/2$ with the horizontal and the location of the log spiral's center.

• Structural Engineering and Mechanics
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• v.67 no.3
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• pp.291-300
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• 2018

In this work, a new trigonometry theory of shear deformation is developed for the static analysis of thick isotropic beams. The number of variables used in this theory is identical to that required in the theory of Euler-Bernoulli, sine function is used in the displacement field in terms of the coordinates of the thickness to represent the effects of shear deformation. The advantage of this theory is that shear stresses can be obtained directly from the relationships constitute, while respecting the boundary conditions at the free surface level of the beam. Therefore, this theory avoids the use of shear correction coefficients. The differential equilibrium equations are obtained using the principle of virtual works. A thick isotropic beam is considered, whose numerical study to show the effectiveness of this theory.

• Structural Engineering and Mechanics
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• v.76 no.1
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• pp.27-56
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• 2020

In this paper, the deflection and buckling analyses of porous nano-composite piezoelectric plate reinforced by carbon nanotube (CNT) are studied. The equations of equilibrium using energy method are derived from principle of minimum total potential energy. In the research, the non-local strain gradient theory is employed to consider size dependent effect for porous nanocomposite piezoelectric plate. The effects of material length scale parameter, Eringen's nonlocal parameter, porosity coefficient and aspect ratio on the deflection and critical buckling load are investigated. The results indicate that the effect of porosity coefficient on the increase of the deflection and critical buckling load is greatly higher than the other parameters effect, and size effect including nonlocal parameter and the material length scale parameter have a lower effect on the deflection increase with respect to the porosity coefficient, respectively and vice versa for critical buckling load. Porous nanocomposites are used in various engineering fields such as aerospace, medical industries and water refinery.