• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.226-229
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• 2006

The safety of on-going ships is one of important concerns in the view of environment and human life. The ship in bad condition is likely to be subjected to accidental loads such as collision. Once she has one or several minor collision damages in the form of circle or ellipse, her ultimate strength under compression or tension load will be reduced. Here, it is important to evaluate the reduction ratio of ultimate strength due to the damage from safety point of view. The problem of strength reduction of a plate with cutout such as opening hole has been treated by many researchers. As a result, a closed-form formula on the reduction of ultimate strength of a plate considering the effect of several forms of cutout was suggested. However, the structure of ships is composed of a plate and a stiffener so-called a stiffened plate, and it is likely to be damaged at a plate and stiffeners together in collision. This paper is to investigate the effect of minor collision damage on ultimate strength of a stiffened plate by using numerical analysis. For this study, the shape of minor collision damage of a stiffened plate was made by using contact algorithm. The deformed shape was used as an initial shape for ultimate stress analysis. Then, a series of nonlinear FE analysis was conducted to investigate the reduction effects of ultimate strength of the stiffened plate. The boundary condition was applied as simply supported at all boundaries, and the tripping of stiffener among failure mode under compression loading was neglected. These results were settled in the form of reduction ratio between ultimate of original intact stiffened plate and that of damaged stiffened plate.

• The Journal of the Korea Contents Association
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• v.10 no.10
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• pp.1-8
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• 2010

Recently, the character image processing technology using portable device camera image at home and abroad are actively conducted, but Practical use are lower rate because of accuracy and time-consuming process problems. In this paper, we propose the license plate recognition method based on geometric information from portable device camera image. In the extracted license plate region we recognize characters using the chain code and the Thickness information through the cumulative projected edge after performing the pre-processing work considering the angle difference, the contrast enhancement and the low resolution from portable device camera image. The proposed algorithm is effective and accurate recognition by light and reducing the processing time. And, the results from the character recognition success rate was 95%. In the future, we will research about license plate recognition algorithm using long distance image or added motion blur image.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.9
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• pp.694-701
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• 2002

In this paper, through the study on locations of structural transducers for active control of the radiated sound from the vibrating plate, the active structural acoustic control (ASAC) system is proposed. And, for the evaluation of the proposed location, the experiment of the active structural acoustic control is implemented using the multi-channel filtered-x LMS algorithm and an additional filter (Acoustic Prediction Filter) to estimate the radiated sound using the acceleration signals of the plate. The structural transducers are piezoceramic actuator (PZT) and accelerometer. PZT is used as an actuator to reduce the vibration and the radiated sound. To maximize the control performance, each PZT actuator is located at the position that has the largest control sensitivity of the plate bending moment in the direction of x and y coordinates and the optimal PZT location is validated experimentally. Also, to find the acoustic prediction filter accurately, two accelerometers are located at the positions that have the largest radiation efficiencies of the plate, and the proposed locations are validated by simulation using the Rayleigh integral. The multi-channel filtered-x LMS algorithm is introduced to control a complex 2-D structural vibration mode. Finding the locations of structural transducers for active structural acoustic control of the radiated sound, the active structural acoustic control (ASAC) system can be presented and validated by experiments using a real time control system.

• The Journal of the Korea Contents Association
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• v.13 no.10
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• pp.19-26
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• 2013

In the Malaysian license plates, alphabets and numerals which are made by plastic, are adhered to a frame as embossing style and occasionally characters in horizontal, vertical directions are aligned with narrow space. So the extraction of character stroke information can be hard in the vehicle images of low illumination intensity. In this paper, Malaysian license plate recognition algorithm for low illumination intensity image is proposed. DoG filtering based character stroke generation method is introduced to derive exact connected components of strokes in the vehicle image of low illumination intensity. After localization of plate by connected component analysis, characters are segmented and recognized. Algorithm is experimented for the 6,046 vehicle images captured in Kuala Lumpur by IR camera without using any special light during day and night. The experimental results show that recognition accuracy of plates is 96.1%.

• Journal of the Korea Society of Computer and Information
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• v.12 no.5
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• pp.313-319
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• 2007

In this paper, we propose a novel method to extract an area of car licence plate and codes of vehicle number from a photographed car image using features on vertical edges and a new Fuzzy neural network algorithm to recognize extracted codes. Prewitt mask is used in searching for vertical edges for detection of an area of vehicle number plate and feature information of vehicle number palate is used to eliminate image noises and extract the plate area and individual codes of vehicle number. Finally, for recognition of extracted codes, we use the proposed Fuzzy neural network algorithm, in which FCM is used as the learning structure between input and middle layers and Max_Min neural network is used as the learning structure within inhibition and output layers. Through a variety of experiments using real 150 images of vehicle, we showed that the proposed method is more efficient than others.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.301-305
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• 2002

Among many structural dynamics modification methods for plate and shell vibration problems, embedding an emboss to the surface is very efficient. But deciding an optimal position and shape using optimization algorithm needs defining geometry and remeshing the model for every iteration step to implement the method, which takes much numerical cost. An equivalent element produced here lessen the cost by representing the geometrical characteristics of an emboss using the element's material properties and thickness becoming a geometrically homogenous element of the base plate or shell. Some efficient factors which let the equivalent system have the same dynamical response as the original system embedded with emboss will be shown and the degree of equivalence will be tested in terms of natural frequency matching.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.237-239
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• 2009

The purpose of this research is to propose a system to detect a strip defect on a iron plate using an image processing, one way of finding defects on an iron plate. An existing way of image processing is using a light source which release a light energy in a certain frequency and a light absorbing display which responds to the light source. This research attempts to detect defects by using the image processing which handles an illumination, without depending on characteristics of light frequency. One of the advantages of this method is that it makes up for the weakness of the existing method which was too difficult for users to notice a defect. Also this method makes it possible to realize a real-time monitoring on a plate of iron.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1113-1116
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• 2003

In this paper, it is suggested that the technology sound measurement which is to search the inferiority of the plate during the pressing. We evaluate whether there is a inferiority by analysing and comparing the satisfactory and inferior plate with the method of a spectrum analysis by measuring the sound which is emitted during pressing. We designed the analysis algorithm to detect inferior plate throughout comparison of measured sound data using FFT, DFT and DASYLab S/W. In addition to these, we suggest the way to compare both inferior and satisfactory signal statistically.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1660-1665
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• 2003

On this study, we improved the efficiency applying algorithm that is repeatedly using orthogonal array in discrete design space and filling a defect of gradient method in continuous design space. we showed optimal ply angle that maximized 1st natural frequency of CFRP laminated composite cantilever plate by each aspect ratio. A finite element analysis on the CFRP laminated composite cantilever plate using orthogonal array is carried out, and the results are compared with those obtained by modal testing.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.226-226
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• 2000

This paper presents the control problem for the motion of sphere with robot manipulator. The robot manipulator is controlled to regulate the angle of plate for the sphere to track given trajectories on the plate. The center position of the sphere is measured with machine vision system and the advanced algorithm for center detection is proposed in which the change of shape is considered to solve the problem of image distortion. To cope with the variation of plate material and the structure of sphere (size, mass, etc.), sliding mode control, which has robustness to model uncertainty, is applied to the control of robot manipulator.