• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 Asia Navigation Conference
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• pp.146-154
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• 2004

Evaluating the risk of collision quantitatively plays a key role in developing the expert system of navigation and collision avoidance. This study suggested and developed a new approach to the evaluation by using the sech function as an alternative to the existing methods of appraising the collision risk. This study also investigated and built up theoretically how to determine the gradient coefficients in this approach and suggested the appropriate values as much as applicable. Finally this study analyzed thoroughly how to determine the threshold function of avoiding time and developed the appropriate equation.

• 한국동물학회지
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• 제37권4호
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• pp.524-530
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• 1994

An Arpase complex has been purified to apparent homogeniety from the extract of chick skeletal muscle using conventional column chromatographies and glycerol density gradient centrifugation. This eWe has a sedimentation coefficient of 15S as determined by the gradient centrifugation and therefore is referred to as the 15S ATPase. It behaves as a 600-kOa molecule upon gel filtration analysis using a Superose-6 column. However, the ATPase runs as a 95-kDa polvpeptide when analyzed by polvacrvlamide gel electrophoresis in the presence of sodium dodecyl sulfate. Thus, the Arpase is likely to consist of six identical subunits of 95 KDa. It has a Km value of 0.6 mM for ATP and is maximally active at pH 9.

• 한국동물학회지
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• 제35권2호
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• pp.231-239
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• 1992

For the analysis of the relative grouch of six body pans, such as carapace width. abdominal length, abdominal width, cheliped length, second pereiopod length and third pereiopod length, to the carapace length of crayfish (Comboroides similis Koelbel), the equation Y = bXa were applied. The results were as follows: 1. In the relative srourth of each body part to the carapace length, abdominal width and abdomial length in both sexes showed as positive allometrv, the third pereiopod length in both sexes as isometry and the rest shouted as negative. The least coefficient of the relative growth was found in cheliped length in female (0.9300).2. The grolwth gradient of each body part to the carapace length in each sex revealed decreasing pattern in abdominal length and third pereiopod length in both sexes and the abdominal width in male with the growth centers on the initial growth period. and the rest showed increasing pattern with the growth centers on the 6th growvth period except the abdomini,d uridth in female on the 3rd growth period.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2004년도 GIS/RS 공동 춘계학술대회 논문집
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• pp.523-528
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• 2004

본 연구는 원격탐사 영상분류 과정에 이방성 분산 복원의 적용을 제안하고 있다. 수정 이방성 분산 복원은 많은 원격탐사 영상에 나타나는 지리적 연결성을 대표하는 Markov random field에 기반한 확률적 모형을 사용하고 있고 반복적인 확산과정을 통해 영상복원을 수행한다. 제안 확산과정은 지리적 연결성과 연관된 응집력 계수를 위하여 brightness gradient의 함수를 사용하며 매 반복단계마다 adaptive하게 추정한다. 한반도의 위성 원격탐사 자료에 대한 실험을 실시하였고 제안된 수정 이방성 분산 복원의 적용은 실제 관측 자료에도 매우 효과적임을 알 수 있었다.

• 한국전기전자재료학회논문지
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• 제19권5호
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• pp.480-485
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• 2006

A research was undertaken on the thermal properties and behavior of the conductors in a controlled chamber, which was designed to implement the outdoor air temperature, heat and wind conditions With ACSR $410mm^2$ overhead conductors, we measured the maximum temperature of the conductors and the temperature gradient from the core to the surface regions as a function of current, tension, wind velocity and outdoor air temperature. This test also provided a comparative analysis between the measured temperature values of conductors in the controlled chamber and the theoretical calculations of ANSI/IEEE at normal condition. There was not much influence of tension on the conductor temperature. However, the compactness of conductor wires increased with an increase in tension, which eventually increased the coefficient of effective thermal conductivity and, accordingly the conductor temperature was reduced more or less.

• 한국기계가공학회지
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• 제5권3호
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• pp.71-79
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• 2006

ABS is a safety device for preventing wheel locking in a sudden baking. Its control methods are classified into three types; deceleration control, wheel slip control and deceleration/acceleration control. The braking force takes the influence of the friction coefficient between road and tire, which in turn depends on the wheel slip as well as road conditions. In this paper, it has been proposed the wheel slip control system to apply the adaptive control method at the ABS. To maintain wheel slip to desired wheel slip, it have been done the linearization and designed the adaptive controller to apply gradient method based on the reference model. It is illustrated by computer simulations that the proposed control system gives good performances and adaptation to parameter variation.

• Steel and Composite Structures
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• 제33권3호
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• pp.403-432
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• 2019

Axially functionally graded (AFG) beams are a new class of composite structures that have continuous variations in material and/or geometrical parameters along the axial direction. In this study, the exact analytical solutions for the free vibration of AFG and uniform beams with general elastic supports are obtained by using Euler-Bernoulli beam theory. The elastic supports are modeled with linear rotational and lateral translational springs. Moreover, the material and/or geometrical properties of the AFG beams are assumed to vary continuously and together along the length of the beam according to the power-law forms. Accordingly, the accuracy, efficiency and capability of the proposed formulations are demonstrated by comparing the responses of the numerical examples with the available solutions. In the following, the effects of the elastic end restraints and AFG parameters, namely, gradient index and gradient coefficient, on the values of the first three natural frequencies of the AFG and uniform beams are investigated comprehensively. The analytical solutions are presented in tabular and graphical forms and can be used as the benchmark solutions. Furthermore, the results presented herein can be utilized for design of inhomogeneous beams with various supporting conditions.

• Advances in nano research
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• 제12권4호
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• pp.427-440
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• 2022

In the present study, the nonlocal strain gradient theory is used to predict the size-dependent buckling and post-buckling behavior of geometrically imperfect nano-scale piezo-flexomagnetic plate strips in two modes of direct and converse flexomagnetic effects. The first-order shear deformation plate theory is used to analyze analytically nano-strips with simply supported boundary conditions. The nonlinear governing equations of equilibrium and associated boundary conditions are derived using the principle of minimum total potential energy with consideration of the von Kármán-type of geometric nonlinearity. A closed-form solution of governing differential equation is obtained, which is easily usable for engineers and designers. To validate the presented formulations, whenever possible, a comparison with the results found in the open literature is reported for buckling loads. A parametric study is presented to examine the effect of scaling parameters, plate slenderness ratio, temperature, the mid-plane initial rise, flexomagnetic coefficient, different temperature distributions, and magnetic potential, in case of the converse flexomagnetic effect, on buckling and post-buckling loads in detail.

• 한국소음진동공학회논문집
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• 제15권3호
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• pp.259-265
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• 2005

A two-degree-of-freedom out-of-plane model with contact stiffness is presented to describe dynamical interaction between the pad and disc of a disc brake system. It is assumed that the out-of-plane motion of the system depends on the friction force acting along the in-plane direction. Dynamic friction coefficient is modelled as a function of both in-plane relative velocity and out-of-plane normal force. When the friction coefficient depends only on the relative velocity, the contact stiffness has the role of negative stiffness. The results of stability analysis show that the stiffness of both pad and disc is equally important. Complex eigen value analysis is conducted for the case that the friction coefficient is also dependent on the normal force. The results further verify the importance of the stiffness. It has also been found that increasing the gradient of friction coefficient with respect to the normal force makes the system more unstable.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.597-600
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• 2004

A two-degree-of-freedom out-of-plane model with contact stiffness is presented to describe dynamical interaction between the pad and disc of a disc brake system. It is assumed that the out-of-plane motion of the system depends on the friction force acting along the in-plane direction. Dynamic friction coefficient is modelled as a function of both in-plane relative velocity and out-of-plane normal force. When the friction coefficient depends only on the relative velocity, the contact stiffness has the role of negative stiffness. The results of stability analysis show that the stiffness of both pad and disc are equally important. Complex eigenvalue analysis is conducted for the case that the friction coefficient is also dependent on the normal force. The results further verify the importance of the stiffness. It has also been found that increasing the gradient of friction coefficient with respect to the normal force makes the system more unstable. Nonlinear analysis is also performed to demonstrate various responses. Comparing the responses with experimental data has shown that the proposed model may qualitatively well represent a certain type of brake noise.