• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.1
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• pp.16-25
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• 2020

Vegetation segmentation in a field color image is a process of distinguishing vegetation objects of interests like crops and weeds from a background of soil and/or other residues. The performance of the process is crucial in automatic precision agriculture which includes weed control and crop status monitoring. To facilitate the segmentation, color indices have predominantly been used to transform the color image into its gray-scale image. A thresholding technique like the Otsu method is then applied to distinguish vegetation parts from the background. An obvious demerit of the thresholding based segmentation will be that classification of each pixel into vegetation or background is carried out solely by using the color feature of the pixel itself without taking into account color features of its neighboring pixels. This paper presents a new pixel-based segmentation method which employs a multi-layer perceptron neural network to classify the gray-scale image into vegetation and nonvegetation pixels. The input data of the neural network for each pixel are 2-dimensional gray-level values surrounding the pixel. To generate a gray-scale image from a raw RGB color image, a well-known color index called Excess Green minus Excess Red Index was used. Experimental results using 80 field images of 4 vegetation species demonstrate the superiority of the neural network to existing threshold-based segmentation methods in terms of accuracy, precision, recall, and harmonic mean.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.114-117
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• 2008

Curved thick plate forming in shipbuilding industry is currently performed by a thermal process, called as Line Heating by using gas flame torches. It was examined as an alternative way in this study to manufacture curved thick plates by the multi-punch die forming. Experiments and finite element analyses were conducted to evaluate the feasibility of the reconfigurable discrete die forming to the thick plates. Configuration of the multi-punch dies suitable for multi-curvature was investigated. As a result, single step forming by reconfigurable discrete die with scale factor improved formability.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.355-358
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• 2008

In order to investigate the physical mechanism of the energy cascade in homogeneous isotropic turbulence, we introduce Galilean-invariant energy and its transfer rate in the real space as a function of position, time and scale. By using a database of direct numerical simulations (DNS) of homogeneous isotropic turbulence, it is shown that (i) fully developed turbulence consists of multi-scale coherent vortices of tubular shapes, (ii) the energy at each scale is mainly confined in vortex tubes with the radii of the same order of the length scale, and (iii) the energy transfer takes place around pairs (especially, anti-parallel pairs) of such vortex tubes. Based on these observations, it is suggested that the energy cascade can be caused, in the real space, by the process of the stretching and creation of smaller (i.e. thinner) vortex tubes by the straining field around pairs of larger (i.e. fatter) vortex tubes. Indeed, it is quite easy to find such events (in our DNS fields) which strongly support this scenario of the energy cascade.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.355-358
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• 2008

In order to investigate the physical mechanism of the energy cascade in homogeneous isotropic turbulence, we introduce Galilean-invariant energy and its transfer rate in the real space as a function of position, time and scale. By using a database of direct numerical simulations (DNS) of homogeneous isotropic turbulence, it is shown that (i) fully developed turbulence consists of multi-scale coherent vortices of tubular shapes, (ii) the energy at each scale is mainly confined in vortex tubes with the radii of the same order of the length scale, and (iii) the energy transfer takes place around pairs (especially, anti-parallel pairs) of such vortex tubes. Based on these observations, it is suggested that the energy cascade can be caused, in the real space, by the process of the stretching and creation of smaller (i.e. thinner) vortex tubes by the straining field around pairs of larger (i.e. fatter) vortex tubes. Indeed, it is quite easy to find such events (in our DNS fields) which strongly support this scenario of the energy cascade.

• Carbon letters
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• v.12 no.3
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• pp.177-179
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• 2011

The use of carbon nanotubes (CNTs) as a reinforcing material in a polymer matrix has increased in various industries. In this study, the flexural behavior of CNT-modified epoxy/basalt (CNT/epoxy/basalt) composites is investigated. The effects of CNT modification with silane on the flexural properties of CNT/epoxy/basalt composites were also examined. Flexural tests were performed using epoxy/basalt, oxidized CNT/epoxy/basalt, and silanized CNT/epoxy/basalt multi-scale composites. After the flexural tests, the fracture surfaces of the specimens were examined via scanning electron microscopy (SEM) to investigate the fracture mechanisms of the CNT/epoxy/basalt multi-scale composites with respect to the CNT modification process. The flexural properties of the epoxy/basalt composites were improved by the addition of CNTs. The flexural modulus and strength of the silane-treated CNT/epoxy/basalt multi-scale composites increased by approximately 54% and 34%, respectively, compared to those of epoxy/basalt composites. A SEM examination of the fracture surfaces revealed that the improvement in the flexural properties of the silane-treated CNT/epoxy/basalt multi-scale composites could be attributed to the improved dispersion of the CNTs in the epoxy.

• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.304-310
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• 2008

Currently energy use planning council system is mandatory especially for the urban development project planned on a specified scale or more. The goal of existing demand prediction was to calculate the maximum load by multiplying energy load per unit area by building size. The result of this method may be exaggerated and has a limit in the information of period load. The paper suggests a new forecasting process based on standard unit household in order to upgrade the limit in demand prediction method of multi-family housing complex. The new process was verified by comparing actual using amount of multi-family housing complex to forecasting value of energy use plan.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.12
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• pp.1113-1119
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• 2000

To operate a process plant safely and economically, process monitoring is very important. Process monitoring is the task to identify the state of the system from sensor data. Process monitoring includes data acquisition, regulatory control, data reconciliation, fault detection, etc. This research focuses on the data recon-ciliation using scale-space filtering and fault detection using functional-link associative neural networks. Scale-space filtering is a multi-resolution signal analysis method. Scale-space filtering can extract highest frequency factors(noise) effectively. But scale-space filtering has too large calculation costs and end effect problems. This research reduces the calculation cost of scale-space filtering by applying the minimum limit to the gaussian kernel. And the end-effect that occurs at the end of the signal of the scale-space filtering is overcome by using extrapolation related with the clustering change detection method. Nonlinear principal component analysis methods using neural network have been reviewed and the separately expanded functional-link associative neural network is proposed for chemical process monitoring. The separately expanded functional-link associative neural network has better learning capabilities, generalization abilities and short learning time than the exiting-neural networks. Separately expanded functional-link associative neural network can express a statistical model similar to real process by expanding the input data separately. Combining the proposed methods-modified scale-space filtering and fault detection method using the separately expanded functional-link associative neural network-a process monitoring system is proposed in this research. the usefulness of the proposed method is proven by its application a boiler water supply unit.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.5
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• pp.435-444
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• 2012

Although the multi-scale map database should be constructed for the web map services and location-based services, much part of generation process is based on the manual editing. In this study, the map generalization methodology for automatic construction of multi-scale database from the primary data is proposed. Moreover, the generalization methodology is applied to the real map data and the prototype of multi-scale map dataset is generated. Among the generalization operators, selection/elimination, simplification and amalgamation/aggregation is applied in organized manner. The algorithm and parameters for generalization is determined experimentally considering T$\ddot{o}$pfer's radical law, minimum drawable object of map and visual aspect. The target scale level is five(1:1,000, 1:5,000, 1:25,000, 1:100,000, 1:500,000) and for the target data, new address data and digital topographic map is used.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.8
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• pp.459-466
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• 2014

Fading effect of old pictures and printings is shown up differently according to the ink property, temperature, humidity, illuminants, and so on. Faded image enhancement techniques based on illuminant estimation are proposed such as the gray world algorithm and white patch retinex methods. However, conventional simple operators are not suitable for enhancing faded images because partial fading effect is appeared differently. Thus, this paper presents a color enhancement algorithm based on integrating correction coefficients for faded images. First, the proposed method adopts local process by using multi-scale average mask. The coefficients for each multi-scale average mask are obtained to apply the gray world algorithm. Then, integrating the coefficients with weights is performed to calculate correction ratio for red and blue channels in the gray world assumption. Finally, the enhanced image is obtained by applying the integrated coefficients to the gray world algorithm. In the experimental results, the proposed method reproduces better colors for both wholly and partially faded images compared with the previous methods.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.169-172
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• 2009

Multiple scale modeling has been applied to predict defect shape change during the wire rod rolling process. The size difference between bloom and defect prevent using usual FEM approaches due to the enormous number of elements required to depict the defect. The newly developed multiple scale model can visualize defect shape changes during the multi stands rolling process. The defect positioned at the top and side of bloom are smoothed out but the one at the middle evolved as folding or remained as crack. This approach can be used for defect control with roll shape design and initial bloom shape.