• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.4
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• pp.58-71
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• 1989

This study aims to develop a computerized program for analysis of the ground-supported cylindrical shell structure with step varied section and to find out its mechanical characteri- stics through application of the developed program to the analysis of a ensiled farm silo as a model structure. The thickness of wall and bottom-plate of farm silo is assumed to be step-varied and its detailed structural dimensions are presented in Tab. 1 and 2. Several numerical case studies show that sectional stresses of the sample structures are largely reduced by adopting "varied section" design technique. And, other major results ob- tained from this study are summarize4 as follows ; 1. The variation of wall-thickness has a great influence on bending stresses of wall. Ho- wever, the larger the relative thickness of bottom-plate is, the smaller the influence is. 2. The magnitude of thickness of projecting toe of bottom-plate has negligible effect on sectional stresses 3. The conventional design methodology, which assumes the bottom edge of wall as clam- ped on ground, is proved to be discarded through the numerical analysis. 4. It is found that the "varied section" design technique should get similar effects as in the case of thick bott6m-plate having uniform thickness. 5. The variation of wall-thickness has a considerable effect on the bending stresses of bo- ttom-plate. Especially, this phenomenon is very remarkable in its projecting toe. In some cases. the negative bending moment may be acted on.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.2
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• pp.446-455
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• 1994

An experimental study is conducted for the turbulent recirculating flow behind a backward-facing step when the oscillating jet is issued sinusoidally through a thin slit at the separation edge. Two key parameters are dealt with in the present experiment, i.e., the amplitude of forcing and the forcing frequency. The Reynolds number based on the step height is varied from 25,000 to 35,000. In order to investigate the effect of local forcing, turbulent structures are scrutinized for both the flow of forcing and the flow of no forcing. The growth of shear layer with a local forcing is larger than that of no forcing. The influence of a local forcing brings forth the decrease of reattachment length and the particular frequency gives a minimum reattachment length. The most effective frequency depends on the non-dimensional frequency, St/sub .theta./, based on the momentum thickness at the separation point. A comparative study leads to the conclusion that the large-scale vortical structure is strongly associated with the forcing frequency and the natural flow instability.

• Korean Journal of Materials Research
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• v.8 no.10
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• pp.950-955
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• 1998

Ar 이온 식각법을 이용하여 (001) SrTiO3(STO) 단결정 기판 위에 200nm 높이의 계단형 모서리를 제작하였다. 계단식은 입사하는 Ar 이온 빔에 대한 Ar 이온 입사각과 마스크 회전각을 조절함으로써 38$^{\circ}$-70$^{\circ}$의 넓은 범위로 제어할 수 있었다. 초전도 YBa2Cu3O7-$\delta$박막은 계단이 있는 STO 기판 위에 펄스레이저 증착법을 이용하여 증착하였으며, 박막의 두께는 계단 높이에 대한 박막의 두께비가 0.5-1.2가 되도록 하였다. 계단형 모서리 조셉슨 접합의 임계전류밀도와 IcRn값은 77K에서 각각 104A/$\textrm{cm}^2$, 70-200$\mu$V이었다.

• International Journal of Computer Science & Network Security
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• v.22 no.11
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• pp.121-126
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• 2022

The number of vehicles has increased exponentially over the past 20 years due to technological advancements. It is becoming almost impossible to manually control and manage the traffic in a city like Karachi. Without license plate recognition, traffic management is impossible. The Framework for License Plate Detection & Recognition to overcome these issues is proposed. License Plate Detection & Recognition is primarily performed in two steps. The first step is to accurately detect the license plate in the given image, and the second step is to successfully read and recognize each character of that license plate. Some of the most common algorithms used in the past are based on colour, texture, edge-detection and template matching. Nowadays, many researchers are proposing methods based on deep learning. This research proposes a framework for License Plate Detection & Recognition using a custom YOLOv5 Object Detector, image segmentation techniques, and Tesseract's optical character recognition OCR. The accuracy of this framework is 0.89.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.163-171
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• 2008

In this paper, we present an adaptive parametric cubic convolution technique in order to enlarge the low resolution image to the high resolution image. The proposed method consists of two steps. During the first interpolation step, we acquire adaptive parameters in introducing a new cost-function to reflect frequency properties. And, the second interpolation step performs cubic convolution by applying the parameters obtained from the first step. The enhanced interpolation kernel using adaptive parameters produces output image better than the conventional one using a fixed parameter. Experimental results show that the proposed method can not only provides the performances of $0.5{\sim}4dB$ improvements in terms of PSNR, but also exhibit better edge preservation ability and original image similarity than conventional methods in the enlarged images.

• Journal of KIISE:Software and Applications
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• v.27 no.8
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• pp.804-814
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• 2000

In this paper, we propose an effective method to detect the regions of interests in the Videostrobokymography System. Videostrobokymography system is a medical image processing system for extracting automatically the diagnosis parameters from the irregular vibratory movements of the vocal fold. We detect the regions of interests through three steps. In the first step, we remove the noise in the input image and we find the minimum energy value in each frame. In the second step, we computed the edge by everage value for the one line. In the third step, the regions of interests can be extracted by using the Merge Algorithm which uses the variance of luminance as the feature points. We experimented this method for the vocal fold images of nineteen patients. In consequence, the regions of interests are detected in most vocal fold images. The method proposed in this study is efficient enough to extract the region of interests in the vocal fold images with the frame rate of 40 frames/second and the resolution of 200${\times}$280 pixels.

• Korean Journal of Remote Sensing
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• v.11 no.3
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• pp.61-70
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• 1995

In this paper, the algorithm to extract the height of flat-rooftop structures in stereo aerial image is suggested with an assumption that location, orientation, focal length, and field of view of a camera are known. It can be adapted to stereo aerial or satellite images. For performing feature-based stereo matching, the line segments suitable to describe the shape of general buildings are chosen as the feature. This paper is composed of three categories;the first step is to extract edges of structures with the polygon extraction algorithm which utilizes the edge following method, the second step is to perform the line segment matching with the camera information, and the last step is to calculate the location of each matched line and to estimate heights. The stereo images used in experiments are not real but synthetic ones. The experiment shows good results.

• The Journal of the Korea Contents Association
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• v.19 no.1
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• pp.125-131
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• 2019

A vanishing point is a point on an image to which parallel lines projected from a real space gather. A vanishing point in a road space provides important spatial information. It is possible to improve the position of an extracted lane or generate a depth map image using a vanishing point in the road space. In this paper, we propose a method of detecting vanishing points on images taken from a vehicle's point of view using Deep Neural Network (DNN) and Histogram of Oriented Gradient (HoG). The proposed algorithm is divided into a HoG feature extraction step, in which the edge direction is extracted by dividing an image into blocks, a DNN learning step, and a test step. In the learning stage, learning is performed using 2,300 road images taken from a vehicle's point of views. In the test phase, the efficiency of the proposed algorithm using the Normalized Euclidean Distance (NormDist) method is measured.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.4
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• pp.333-340
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• 1990

The authors carried out a visiualizational model test by the hydrogen bubble method to examine the pattern of the fluid flow besides the simple camber type and plane type otter board in circulation water channel. The experimental conditions are velocity of flow 0.05 and 0.1m/sec, angle of attack 0$^{\circ}$~45$^{\circ}$(5$^{\circ}$step). The results obtained are as follows: 1. In the case of the simple camber type otter board located angle of attack 25$^{\circ}$, vortex at the leading edge was geneated at 1/2 of chord length. 2. Size of the vortex generated in the trailing edge was about 2~3 times larger then that of the leading edge. 3. In the case of the simple camber type otter board located angle of attack 30$^{\circ}$, separation of stream-line at leading edge was generated at 1/3 of chord length. 4. Nearest stream-line in the back side of the simple camber type otter board was bent in the direction of otter board when the angle of attack was 25$^{\circ}$ and 30$^{\circ}$, and in the case of plane type otter board was expanded outside of the flow direction. 6. Area separated of the simple camber type otter board at the angle of attack 30$^{\circ}$ was smaller then that of plane type otter board. 7. Flow speed in the back side of the simple camber type otter board was about 1.4 times faster then that in the front side, and in the case of the plane otter board about 1.2 times faster.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.9
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• pp.182-189
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• 2014

A tapped delay line time-to-digital converter (TDC) can be easily implemented using internal carry chains in a field-programmable gate array, and hence, its use is widespread. However, the tapped delay line TDC suffers from performance degradation because of differences in the delay times of dedicated carry chains. In this paper, a dual edge measurement method is proposed instead of a typical step signal to the delay cell to compensate for the performance degradation caused by wide-delay cells in carry chains. By applying a pulse of a fixed width as an input to the carry chains and using the time information between the up and down edges of the signal pulse, the timing accuracy can be increased. Two dedicated carry chain sites are required for the dual edge measurements. By adopting the proposed dual edge measurement method, the average delay widths of the two carry chains were improved by more than 35%, from 17.3 ps and 16.7 ps to 11.2 ps and 10.1 ps, respectively. In addition, the maximum delay times were improved from 41.4 ps and 42.1 ps to 20.1 ps and 20.8 ps, respectively.