• Journal of Industrial Technology
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• v.20 no.B
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• pp.21-26
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• 2000

Heat loss, fin effectiveness and efficiency of a plate fin are investigated as a function of non-dimensional fin length and Biot number using a two-dimensional separation of variables method. The value of temperature of the left side is set to be different from that of the right side for this plate fin to satisfy the real physical condition. Also temperature distribution within this plate fin is listed. One of the results shows that the fin can be considered to be useful in view of fin effectiveness on the given range of Biot number when non-dimensional fin length is larger than 3.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.722-725
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• 2014

The spatial focusing of time reversal Lamb waves on a plate has attracted considerable attention for identifying the location of an input source. This study investigates the spatial focusing performance on a plate with respect to the number of piezoelectric (PZT) sensors for varying locations of input sources. In particular, a small number of PZT sensors produce spatial focusing through the virtual sensor effect due to reflection of Lamb waves at plate edges. The spatial focusing performance with respect to the number of PZT sensors is quantified in terms of signal to noise ratio through numerical simulation and its implication is discussed.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.6
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• pp.173-181
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• 2000

The stability of a structural plate is a crucial problem which causes wrinkling and buckling. In this paper, the effect of the pattern of spot-welding points in the two rectangular plate on the shear buckling load is studied with respect to the thickness, the aspect ratio of plates, the number of welding spots. Buckling coefficient of the simple plate was compared with that of two plates with various conditions to extract the effect of buckling strength. The effect of the number of welding spots are studied in two directions, longitudinal and transverse directions. The concluded that the reinforcement effect was maximized when the aspect ratio was close to 1.5 and that the effect of number of welding spots in longitudinal direction was larger than that in transverse direction.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2003.06a
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• pp.102-105
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• 2003

Up to the present studies of the car number recognition system, it is generally known to have serious problems such as relatively long processing time due to the excessive length of data extracted from the number plate based on the current image characteristics, and the image blurring with the physical damage of the brightness and darkness signals of the number plate caused by external impulses with many difficulties in the extraction of the highlighted numbers. In this Paper we used the characteristics firstly having a constant brightness of number plate, and a high density to the horizontal axis, and the influences of highlighted signal could be reduced by making reflections less through the polarized filter on the camera for any highlighted signal. For the more, the data processing time and the noise reduction are effectively implemented by using the wavelet transform of time-space scale with the considerations on the physical loss and processing time.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.423-426
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• 1995

An image processing algorithm is developed in order to recognize the type of cars, the position of a number plate and the characters on the plate. To recognize the type af cars, comparison of two images is used. One has a car image, the other is just a background image without car. After that recognition, a vertical line filter is used to find the location of the plate. Finally the similarity method is used to recognize the numbers on the plates.

• Journal of the Korean Solar Energy Society
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• v.27 no.3
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• pp.149-154
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• 2007

It is essential to know the heat transfer characteristics at the absorber plate of Flat-plate solar collector for optimum design. For flat-plate solar collector, it is difficult to experimentally study the effect for the Reynolds number of riser considering low mass flow rate being applied into the collector with one riser tube. So, this study were performed to show the heat transfer characteristics of flat-plate solar collector with single absorber plate and riser for various Reynolds number at riser using commercial code FLUENT 6.0. The base collector size is chosen with $0.4m^2$ as 0.2m by 2m with single riser in this study, Reynolds number at riser is from 200 to 1200 including about 530 at typical flat-plate collector with 10 risers considering the mass flow rate of 0.02kg/s per collector area for the certificate test Through the simulation, the results were presented as the temperature distribution at the absorber plate for various flow rate and solar irradiance conditions, then showed the effective length scale of the absorber plate The real solar irradiation condition is assumed as the constant heat flux condition of $500w/m^2$ considering the annual average solar irradiance in Korea.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.6
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• pp.1026-1036
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• 2004

In this study, single-phase heat transfer experiments were conducted with Oblong Shell and Plate heat exchanger using water. An experimental water loop has been developed to measure the single-phase heat transfer coefficient and pressure drop in a vertical Oblong Shell and Plate heat exchanger. Downflow of hot water in one channel receives heat from the cold water upflow of water in the other channel. Similar to the case of a plate heat exchanger, even at a very low Reynolds number, the flow in the Oblong Shell and Plate heat exchanger remains turbulent. The present data show that the heat transfer coefficient and pressure drop increase with the Reynolds number. Based on the present data, empirical correlations of the heat transfer coefficient and pressure drop in terms of Nusselt number and friction factor were proposed. Also, performance prediction analyses for Oblong Shell and Plate heat exchanger were executed and compared with experiments. $\varepsilon$-NTU method was used in this prediction program. Independent variables are flow rates and inlet temperatures. Compared with experimental data, the accuracy of the program is within the error bounds of $\pm$5% in the heat transfer rate.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.9
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• pp.1531-1540
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• 2016

In this paper, we propose vehicle license plate recognition system based on Radial Basis Function Neural Networks (RBFNNs) with the use of local binarization functions and canny edge algorithm. In order to detect the area of license plate and also recognize license plate numbers, binary images are generated by using local binarization methods, which consider local brightness, and canny edge detection. The generated binary images provide information related to the size and the position of license plate. Additionally, image warping is used to compensate the distortion of images obtained from the side. After extracting license plate numbers, the dimensionality of number images is reduced through Principal Component Analysis (PCA) and is used as input variables to RBFNNs. Particle Swarm Optimization (PSO) algorithm is used to optimize a number of essential parameters needed to improve the accuracy of RBFNNs. Those optimized parameters include the number of clusters and the fuzzification coefficient used in the FCM algorithm, and the orders of polynomial of networks. Image data sets are obtained by changing the distance between stationary vehicle and camera and then used to evaluate the performance of the proposed system.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1835-1844
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• 2022

Single-orifice plate is wildly utilized in the piping system of the nuclear power plant to throttle and depressurize the fluid of the pipeline. The cavitation induced by the single-orifice plate may cause some serious vibration of the pipeline. This study aims to find the optimal designs of the single-orifice plates that may have weak cavitation possibilities. For this purpose, a new single-orifice plate with a convergent-flat-divergent hole was modeled, a multi-objective optimization method was proposed to optimize the shape of a single-orifice plate, while computational fluid dynamics method was adopted to obtain the fluid physical quantities. The reciprocal cavitation number and the developmental integral were treated as cavitation indexes (e.g., objectives for the optimization algorithm). Two non-dominant designs ultimately achieved illustrated obvious reduction in the cavitation indexes at a Reynolds number Re = 1 ×10⁵ defined based on fluid velocity. Besides, the sensitivity analysis and temperature effects were also performed. The results indicated that the convergent angle of the single-orifice plate dominants the cavitation behavior globally. The optimal designs of single-orifice plates result in lower downstream jet areas and lower upstream pressure. For a constant Reynolds number, the higher temperature of liquid water, the easier it is to undergo cavitation. Whereas there is a diametric phenomenon for a constant fluid velocity. Moreover, the regression models were carried out to establish the mathematical relation between temperature and cavitation indexes.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.3
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• pp.46-52
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• 1998

In this paper, after inputting the computer with the attached number plate on the vehicle, using it, the color decomposition method and back propagation neural network proposed the extractable method of the vehicle number plate at high speed. This method separated R, G, B signal form input moving vehicle image to computer through video camera, then after transform this R, G, B signal into input image data of the computer by using color depth of vehicle number plate and store up binary value in the memory frame buffer. After adapting character's recognition algorithm, also improving this, by adapting back propagation neural network makes the vehicle number plate recognition system. Also minimalizing the similar color's confusion, adapting horizontal and vertical extracting algorithm by using the vehicle's rectangular architecture shows the extract and character's recognition of the vehicle number plate at high speed.