• 전기학회논문지P
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• 제57권1호
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• pp.14-21
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• 2008

In this paper, we propose an adaptive contrast enhancement method using dynamic range segmentation. Histogram Equalization (HE) method is widely used for contrast enhancement. However, histogram equalization method is not suitable for commercial display because it may cause undesirable artifacts due to the significant change in brightness. The proposed algorithm segments the dynamic range of the histogram and redistributes the pixel intensities by the segment area ratio. The proposed method may cause over compressed effect when intensity distribution of an original image is concentrated in specific narrow region. In order to overcome this problem, we introduce an adaptive scale factor. The experimental results show that the proposed algorithm suppresses the significant change in brightness and provides wide histogram distribution compared with histogram equalization.

• Structural Engineering and Mechanics
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• 제36권4호
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• pp.421-445
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• 2010

In this paper the formulation of an efficient frame element applicable for nonlinear analysis of 3D reinforced concrete (RC) frames is outlined. Interaction between axial force and bending moment is considered by using the fibre element approach. Further, section warping, effect of normal and tangential forces on the torsional stiffness of section and second order geometrical nonlinearities are included in the model. The developed computer code is employed for nonlinear static analysis of RC sub-assemblages and a simple approach for extending the formulation to dynamic cases is presented. Dynamic progressive collapse assessment of RC space frames based on the alternate path method is undertaken and dynamic load factor (DLF) is estimated. Further, it is concluded that the torsional behaviour of reinforced concrete elements satisfying minimum standard requirements is not significant for the framed structures studied.

• Advances in nano research
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• 제8권2호
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• pp.157-167
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• 2020

This paper studies forced vibrational behavior of porous nanocrystalline silicon nanoshells under radial dynamic loads using strain gradient theory (SGT). This type of material contains many pores inside it and also there are nano-size grains which define the material character. The formulation for nanocrystalline nanoshell is provided by first order shell theory and a numerical approach is used in order to solve nanoshell equations. SGT gives a scale factor related to stiffness hardening provided by nano-grains. For more accurate description of size effects due to nano-grains or nano-pore, their surface energy influences have been introduced. Surface energy of inclusion exhibit extraordinary influence on dynamic response of the nanoshell. Also, dynamic response of the nanoshell is affected by the scale of nano-grain and nano-pore.

• 한국기계가공학회지
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• 제8권3호
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• pp.98-104
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• 2009

The objective of this paper is to investigate the effect of factors on the dynamic stiffness variation of boring bar. The experiment was carried out by Taguchi Method and Orthogonal array table. The results indicate that overhang was found out to be dominant factor with 95% confident intervals and feed rate and depth of cut were insignificant. In addition, analysis of loss function shows that loss value increased sharply from 3D to 4D(D is a shank diameter). Consequently, there is critical point which changes property of dynamic stiffness.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.854-859
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• 2005

The major objective of this study is to investigate the dynamic behaviors of track due to the deterioration characteristics of ballast for servicing tracks by the field test. The durability of ballast plays an important role in the track behaviour. To estimate the deterioration characteristics of ballast, several tests have been carried out by several shcolars. The deterioration characteristics of ballast is one of the most important factor in the dynamic behaviour of track and its life. In this paper abrasion/breakage characteristics of ballast is studied to predict the effect of physical ballast characteristics on ballast track. To reveal deterioration characteristics of ballast, the field test were carried out. The deterioration characteristics, studied in this paper, is applied to the dynamic behaviour of track in various conditions.

• 반도체디스플레이기술학회지
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• 제14권3호
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• pp.37-43
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• 2015

In this paper, a new background subtraction algorithm for video based fence monitoring surveillance systems is proposed. We adopt the sampling based background subtraction technique and focus on the two main issues: handling highly dynamic environment and handling the flickering nature of pulse based IR (infrared) lamp. Natural scenes from fence monitoring system are usually composed of several dynamic entities such as swaying trees, moving water, waves and rain. To deal with such dynamic backgrounds, we utilize the confidence factor for each background value of the input image. For the flickering IR lamp, the original sampling based technique is extended to handle double background models. Experimental results revealed that our method works well in real fence monitoring surveillance systems.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(I)
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• pp.721-726
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• 2002

The topic on today is dynamic response analysis of curved bridge-AGT(Automated Guide-way Transit) vehicle interaction system. Rubber wheel type AGT vehicle is adopted in this study, and the vehicle is idealized as three dimensional eleven DOF model. Three types of composited steel box girder bridges are modelized with F.E. method. And three types of artificially generated surface roughnesses are adopted for analysis. The dynamic equations of curved bridge, AGT vehicle and surface roughness are derived by using Lagrange's equation of motion. And the equations are solved by Newmark-${\beta}$ method. As a result, The dynamic increasement factor is inverse proportional to radius curvature.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.494-507
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• 2006

The major objective of this study is to investigate the dynamic behaviors of track due to the deterioration characteristics of ballast for servicing tracks by the field test. The durability of ballast plays an important role in the track behaviour. To estimate the deterioration characteristics of ballast, several tests have been carried out by several scholars. The deterioration characteristics of ballast is one of the most important factor in the dynamic behaviour of track and its life. In this paper abrasion/breakage characteristics of ballast is studied to predict the effect of physical ballast characteristics on ballast track. To reveal deterioration characteristics of ballast, the field test were carried out. The deterioration characteristics, studied in this paper, is applied to the dynamic behaviour of track in various conditions.

• International Journal of Safety
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• 제9권2호
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• pp.16-21
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• 2010

In this study, the variations of transformed impact factors and load carrying capacity of highway bridges measured from the state of expansion joint are evaluated. the field loading tests were performed on the highway bridge with damaged expansion joint to investigate the variation of the load carrying capacity. From the field loading tests in case that damaged expansion joint exist or do not exist, the static displacements and dynamic displacements were measured, and TIF were calculated, respectively. dynamic test is performed in order to estimate dynamic displacement and TIF according to the level of damage of expansion joint. From the results of TIF, the load carrying capacity of highway bridges with damaged expansion joint were estimated.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.404-408
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• 2005

Having flexibility in a manipulator will degrade trajectory tracking control and manipulator tip positioning. In practice, however, constraints imposed by various operating requirements, will render the presence of such flexibility unavoidable. The dynamic analysis of the flexible manipulator is essential in designing proper control systems. A flexible manipulator consists of infinite number of elastic modes and the modes are usually coupled to each other. For the practicality, however, it is usually assumed that the flexible system consists of finite number of elastic modes and the modes are decoupled. These assumptions result in a linear and decoupled mathematical model of the flexible manipulator and simplify the analysis of the dynamic behavior and the design of the control system. The decoupling and linearization of the flexible link, however, has been assumed without in depth analysis. This paper focuses on the analysis of the significance of the non-linear coupling factors.