• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.9
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• pp.722-730
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• 2018

This paper presents an analysis technique for estimating the properties of a target's power-spill patterns observed in reconstructed SAR images, which in turn depend on the setup squint angle of the FMCW signal-based SAR system. The target responses observed in the reconstructed SAR images were affected by the range-direction and azimuth-direction of a wave projected on the ground, and the obtained results were analyzed by applying three-dimensional squinted SAR geometry. Furthermore, the rotation patterns were verified through simulations based on the FMCW signal model and back-projection algorithm. This paper summarizes the obtained evaluation results as a function of SAR geometry and squint angle.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.3
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• pp.1-11
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• 2011

The typical truss-lattice material successively packed by repeated cubic symmetric unit cells consists of sub-elements (SE) proposed in this study. The representative continuum model for this truss-lattice material such as the effective strain and stress relationship can be formulated by the homogenization procedure based on the notation of averaged mechanical properties. The volume fractions of micro-scale struts have a significant influence on the effective strength as well as the relative density in the lattice plate with replicable unit cell structures. Most of the strength contribution in the lattice material is induced by axial stiffness under uniform stretching or compression responses. Therefore, continuum based constitutive models composed of homogenized member stiffness include these mechanical characteristics with respect to strength, internal stress state, material density based on the volume fraction and even failure modes. It can be also recognized that the stress state of micro-scale struts is directly associated with the continuum constitutive model. The plastic flow at the micro-scale stress can extend the envelope of the analytical stress function on the surface of macro-scale stress derived from homogenized constitutive equations. The main focus of this study is to investigate the basic topology of unit cell structures with the cubic symmetric system and to formulate the plastic models to predict pressure dependent macro-scale stress surface functions.

• Journal of Biomedical Engineering Research
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• v.19 no.4
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• pp.423-429
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• 1998

Human pharynx is unique, acting as a complex interchange between the oral cavity and esophagus, and between the nasal cavity and lungs. It is actively involved in the transport of food and liquid, producing the forces that guide that bolus into the upper esophagus and away from the adjacent larynx and lungs. This study intended to develop a biomechanical model of the human pharynx, utilizing Finite Element Method(FEM). Within each model changes in cross sectional intralumenal area were calculated and compared with the area from the computer-generated FE model. Area matching allowed estimation of intraluminal pressure gradients during swallow. The estimated pharyngeal pressure gradient varies from one region to another. The estimated pharyngeal pressure gradients showed different patterns for upper four levels and lower four levels. The contraction velocity for upper four levels is much higher than lower four levels. The higher contraction velocities and pressure gradients in the upper levels are consistent with the bolus velocities required for efficient swallow.

• Tunnel and Underground Space
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• v.14 no.3
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• pp.215-228
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• 2004

Rock mass contains discontinuities such as faults and joints, and their mechanical properties and spatial distribution dominate the stability of rock mass. Because the deformation of rock mass occurs discontinuities in many cases. However in the case of poor quality rock mass under high stresses, the deformation along intact rock can also influence the structure's stability. In this study, two dimensional finite element program was developed with a rheological model to analyze the stability of the structure excavated in jointed rock mass. The “equivalent material” approach was used assuming intact rock, joints and rock bolts as visco-plastic materials. The program was verified by analysing an intact rock model, a jointed rock mass model and a reinforced jointed rock mass model. The displacement was examined in each model with changing the intact rock behaviour as elastic and visco-plastic. In the case of poor quality rock mass under high stresses, e assumption of visco-plastic behaviour of intact rock resulted in larger displacement than when assuming elastic behaviour for intact rock. Therefore it is recommended to add intact rock's visco-plastic behaviour to the existing model, which only assumes visco-plastic behaviour of joints and rock bolts.

• Journal of Ocean Engineering and Technology
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• v.31 no.1
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• pp.36-46
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• 2017

Most of the studies on the hydraulic characteristics of wave-current interaction have used 2-D hydraulic experiments or 2-D numerical simulations. However, it is difficult to understand the wave-current interaction found in actual estuaries using these. Therefore, a numerical water tank was constructed in this study to perform simulations involving a 3-D river mouth. The result showed a change in the water surface at the river mouth from the wave-current interaction. With an increase in the ratio ($V_c/C_i$) between the river current and wave celerity, the wave height and mean water level of the river increased at the wave and current meeting point. A higher $V_c/C_i$ caused a stronger wave-current interaction and increased the turbulence kinetic energy. Thus, the wave height attenuation became larger by the wave-current interaction with a higher $V_c/C_i$. In addition, it was possible to understand the flow characteristics in the vicinity of the river mouth as a result of the wave-current interaction using the mean flow and mean time-averaged velocity at the mid-cross section of river.

• Journal of Korean Philosophical Society
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• no.120
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• pp.217-250
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• 2018

Subjekt oder $Selbstbewu{\ss}tsein$ ist ein grundlegendes Prinzip neuzeitlicher Philosophie. Das $Selbstbewu{\ss}tsein$ ist bei Kant $Selbstbewu{\ss}tsein$(analytische Einheit der Apperzeption als klare Selbstbeziehung) in Objekts $bewu{\ss}tsein$(synthetischer Einheit der Apperzeptuion). Dabei zeigt er ein Reflexionsmodell des $Selbstbewu{\ss}tseins$. Aber er $erkl{\ddot{a}}rt$ nicht systematisch ein $Verh{\ddot{a}}ltnis$ zwischen synthetischer Einheit und analytischer Einheit der Apperzeption, und auch $l{\ddot{o}}st$ er nicht theorienimmanente und formale Schwierigkeiten von Zirkelargument bzw. unendlicher Iteration in der Reflxionsstruktur des $Selbstbewu{\ss}tseins$. Aufgrund der Voraussetzungen seiner eigenen Fundamentalontologie kritisiert der $fr{\ddot{u}}he$ Heidegger, $da{\ss}$ Kants $traditionsabh{\ddot{a}}ngige$ $Subjektivit{\ddot{a}}tstheorie$ Symptome der Seins vergessenheit zeigt, transformiert Kants $Selbstbewu{\ss}tseinstheorie$, interpretiert Kants transformierte Theorie als $subjektivit{\ddot{a}}tstheoretische$ $Begr{\ddot{u}}ndung$ der traditionellen Ontologie von Vorhandenheit, und versteht sie als ersten Schritt und erstes phlosophisches Modell seiner Fundamentalontologie. Durch kritische Interpretation von Kants Lehre von Selbstaffektion und $Selbstbewu{\ss}tsein$ deutet er ein Modell des $Selbstbewu{\ss}tseins$ als des $ph{\ddot{a}}nomenologischen$ $Horizontsbewu{\ss}tseins$ an. In diesem Modell der vorreflexiven und unmittelbaren Selbstbeziehung entstehen Schwierigkeiten von Zirkelargument bzw. unendlicher Iteration nicht. Apel kritisiert Kants $selbstbewu{\ss}te$ Apperzeptionstheorie in dem Sinne, $da{\ss}$ sie solipsistisch sei, und in seiner Transzendentalpragmatik $vervollst{\ddot{a}}ndigt$ er Kants transzendentalphilosophische $G{\ddot{u}}ltigkeit$ in der Dimension von $Intersubjektivit{\ddot{a}}t$ diskurierender Menschen. Hierbei ersetzt die Kommunikationsgemeinschaft Kants Apperzeption oder $Bewu{\ss}tsein$ ${\ddot{u}}berhaupt$. In der transzendentalpragmatischen Sicht, die auf den sprachlichen Bezug des Denkens und Erkennens und die Kommunikationsgemeinschaft geht, beruht das $Selbstbewu{\ss}tsein$ oder die Reflexion des Subjekts wesentlich auf seinem sprachlich vermittelten sozialen Bezug. Also geht es nicht um Zirkelargument und unendliche Iteration in denkender Selbstbeziehung des Subjekts. Ebeling hebt Heideggers Daseinsanalytik auf das Niveau von Apels Transzendentalpragmatik an und entwickelt Fundamatalpragmatik ${\ddot{u}}ber$ $Widerstandsbewu{\ss}tsein$ gegen allgemeinen Tod. Dieser $Widerstandsbewu{\ss}tsein$ ist fundamentalpragmatische Transformation von Kants $Selbstbewu{\ss}tsein$. Der $Widerstandsbewu{\ss}tsein$ der Vernunft bleibt in der solipsistischen Dimension nicht und ist ein $Bewu{\ss}tsein$, das in der Widerstandsgemeinschaft durch Argumentation universalisiert werden kann. Hierbei geht es nicht um Zirkelargument und unendliche Iteration.

• Composites Research
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• v.17 no.3
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• pp.29-37
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• 2004

The aeroelastic stability analysis of composite bearingless rotors is investigated using a large deflection beam theory in hover. The bearingless rotor configuration consists of a single flexbeam with a wrap-around type torque tube and the pitch links located at the leading edge and trailing edge of the torque tube. The outboard main blade, flexbeam and torque tube are all assumed to be an elastic beam undergoing flap bending, lead-lag bending, elastic twist and axial deflections, which are discretized into beam finite elements. For the analysis of composite bearingless rotors, flexbeam is assumed to be a rectangular section made of laminate. Two-dimensional quasi-steady strip theory is used for aerodynamic computation. The finite element equations of motion for beams are obtained from Hamilton's principle. The p-k method is used to determine aeroelastic stability boundary. Numerical results are presented for selected bearingless rotor configurations based on the lay-up of laminae in the flexbeam and pitch links location. A systematic study is made to identify the importance of the stiffness coupling terms on aeroelastic stability for various fiber orientation and for different configuration.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5A
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• pp.833-840
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• 2006

In design of steel column member using TMCP steels, hysteretic behavior characteristics of steel column must be clarified. To predict hysteretic behavior of steel column using TMCP steels, a cyclic plasticity model is necessary which can consider the mechanical characteristics and stress-strain relationship of TMCP steels. In this paper, a cyclic plasticity model of SM490-TMC was formulated based on monotonic and cyclic loading tests. The formulated cyclic plasticity model was applied to 3-dimensional finite element analysis. Hysteretic behavior characteristics of steel circular column and H-section column using SM490-TMC was presented by carrying out numerical analysis. Also, influence of SM490-TMC on hysteretic behavior of steel column was presented by comparing analysis results both SM490 and SM490-TMC steel column.

• Science of Emotion and Sensibility
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• v.14 no.2
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• pp.191-196
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• 2011

Fabric extraction force measured through nozzle tester reflects a comprehensive fabric handle. Nozzle tester takes advantage of low cost, and simple and fast operating procedure compared with KES system. The paper is to develop the semi-emprical equation for assessment of the fabric handle measured with nozzle tester on the basis of friction law. The variables considered in the equation arc fabric's frictional coefficient and drape coefficient which is determined in terms of fabric bending length and shear strain. The experiment of 12 different cotton and polyester fabrics and comparisons between experimental and theoretical results were conducted. Fabrics of high frictional coefficients, high bending length, and low shear strain showed high fabric handle forces (low handle values). The handle forces predicted from the equation agreed well with those measured, which indicates that the equation can be used to objectively evaluate fabric handle with respect to fabric's own properties and also provide an information for fabric design to improve the handle performance.

• Journal of the Korea Computer Graphics Society
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• v.20 no.1
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• pp.1-11
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• 2014

Patients with cerebral palsy or arthritis have deformities in lower limb which cause unstable gait or posture and pains. Surgeons perform a deformity correction osteotomy with surgical plan. But sometimes they find the unexpected angular or rotational deformation after surgery. The problems are that there is no method to predict the result of a surgical plan and also there are so many factors to must consider in surgical planning step such as clinical measurements, rotation angle, wedge angle, morphology of lower limb, etc. This paper presents new methods for planning the deformity correction osteotomy efficiently. There are two approaches based on the 3D mesh model and the accurate assessment of the patient's lower limb. One is the manual pre-simulation of surgery using forward kinematics. And the other is the automatic surgical planning using inverse kinematics and nonlinear optimization. Using these methods, we can predict and verify the results of various surgical treatments and also we can find a more effective surgical plan easily compared to conventional methods.