• The Transactions of the Korea Information Processing Society
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• v.7 no.8
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• pp.2565-2574
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• 2000

The error diffusion method is good for reproducing continuous image to binary image. However the reproduction of edge characteristic is weak in power spectrum analysis of display error. In this paper. we present an edge-enhanced error-diffusion method which include pre-processing algorithm for edge characteristic enhancement. Pre-processing algorithm consists of the difference value between current pixel and local average of original image and weighting function of pre-filter. First. it is obtained the difference value between current pixel and the local average of peripheral pixels(5x5) in original image. Second, weighting function of pre-filter is composed by function including absolute value and sign of difference value. The improved Error diffusion algorithm using pre-processing algorithm, present a good result visually which edge characteristic is enhanced. The performance of the proposed algorithm is compared with that of the conventional edge-enhanced error diffusion by measuring the RAPSD of display error, the egde correlation and the local average accordance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.3
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• pp.419-430
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• 1999

Measurements of local blowing ratio and ammonia-diazo flow visualizations have been conducted for a shower-head film cooling on a first-stage turbine stator. In this study, six rows of normal holes are drilled symmetrically on the semicircular leading edge of a simulated blunt body. The measurements show that for an average blowing ratio based on freestream velocity, M, of 0.5, local average mass flow rate through the first two rows of the holes is less than those through the second and third two rows of the holes, and the fraction of mass flow rate through the first two rows to total mass flow rate has a tendency to increase with the increment of M. The flow visualizations reveal that the injection through the first two row results in inferior film coverage even In the case of M = 0.5, meanwhile the row of holes situated at farther downstream location provides higher film-cooling performances for all tested M. This is because film-cooling effectiveness depends on local mainflow velocity at the hole location as well as the mass flow rate through each row.

• Journal of Information Processing Systems
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• v.13 no.5
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• pp.1372-1381
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• 2017

In this paper, a texture feature extraction method using local energy and local correlation of Gabor transformed images is proposed and applied to an image retrieval system. The Gabor wavelet is known to be similar to the response of the human visual system. The outputs of the Gabor transformation are robust to variants of object size and illumination. Due to such advantages, it has been actively studied in various fields such as image retrieval, classification, analysis, etc. In this paper, in order to fully exploit the superior aspects of Gabor wavelet, local energy and local correlation features are extracted from Gabor transformed images and then applied to an image retrieval system. Some experiments are conducted to compare the performance of the proposed method with those of the conventional Gabor method and the popular rotation-invariant uniform local binary pattern (RULBP) method in terms of precision vs recall. The Mahalanobis distance is used to measure the similarity between a query image and a database (DB) image. Experimental results for Corel DB and VisTex DB show that the proposed method is superior to the conventional Gabor method. The proposed method also yields precision and recall 6.58% and 3.66% higher on average in Corel DB, respectively, and 4.87% and 3.37% higher on average in VisTex DB, respectively, than the popular RULBP method.

• Structural Engineering and Mechanics
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• v.38 no.4
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• pp.529-547
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• 2011

This paper presents the global-local finite cover method (GL-FCM) that is capable of analyzing structures involving local heterogeneities and propagating cracks. The suggested method is composed of two techniques. One of them is the FCM, which is one of the PU-based generalized finite element methods, for the analysis of local cohesive crack growth. The mechanical behavior evaluated in local heterogeneous structures by the FCM is transferred to the overall (global) structure by the so-called mortar method. The other is a method of mesh superposition for hierarchical modeling, which enables us to evaluate the average stiffness by the analysis of local heterogeneous structures not subjected to crack propagation. Several numerical experiments are conducted to validate the accuracy of the proposed method. The capability and applicability of the proposed method is demonstrated in an illustrative numerical example, in which we predict the mechanical deterioration of a reinforced concrete (RC) structure, whose local regions are subjected to propagating cracks induced by reinforcement corrosion.

• Korean Journal of Materials Research
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• v.13 no.4
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• pp.233-238
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• 2003

Ferromagnetic tunnel junctions, Ta/Cu/Ta/NiFe/Cu/$Mn_{75}$ $Ir_{25}$ $Co_{70}$ $Fe_{30}$/Al-oxide, were fabricated by do magnetron sputtering and plasma oxidation process. The effect of annealing temperature on the local transport properties of the ferromagnetic tunnel junctions was studied using contact-mode Atomic Force Microscopy (AFM). The current images reflected the distribution of the barrier height determined by local I-V analysis. The contrast of the current image became more homogeneous and smooth after annealing at $280^{\circ}C$. And the average barrier height $\phi_{ave}$ increased and its standard deviation $\sigma_{\phi}$ X decreased. For the cases of the annealing temperature more than $300^{\circ}C$, the contrast of the current image became large again. And the average barrier height $\phi_{ave}$ decreased and its standard deviation $\sigma_{\phi}$ increased. Also, the current histogram had a long tail in the high current region and became asymmetric. This result means the generation of the leakage current that is resulted from the local generation of a low barrier height region. In order to obtain the high tunnel magnetoresistance(TMR) ratio, the increase of the average barrier height and the decrease of the barrier height fluctuation must be strictly controlled.led.

• Journal of Environmental Science International
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• v.24 no.1
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• pp.81-96
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• 2015

The characteristics of atmospheric dispersion of radioactive material (i.e. $^{137}Cs$) related to local wind patterns around the Kori nuclear power plant (KNPP) were studied using WRF/HYSPLIT model. The cluster analysis using observed winds from 28 weather stations during a year (2012) was performed in order to obtain representative local wind patterns. The cluster analysis identified eight local wind patterns (P1, P2, P3, P4-1, P4-2, P4-3, P4-4, P4-5) over the KNPP region. P1, P2 and P3 accounted for 14.5%, 27.0% and 14.5%, respectively. Both P1 and P2 are related to westerly/northwesterly synoptic flows in winter and P3 includes the Changma or typhoons days. The simulations of P1, P2 and P3 with high wind velocities and constant wind directions show that $^{137}Cs$ emitted from the KNPP during 0900~1400 LST (Local Standard Time) are dispersed to the east sea, southeast sea and southwestern inland, respectively. On the other hands, 5 sub-category of P4 have various local wind distributions under weak synoptic forcing and accounted for less than 10% of all. While the simulated $^{137}Cs$ for P4-2 is dispersed to southwest inland due to northeasterly flows, $^{137}Cs$ dispersed northward for the other patterns. The simulated average 137Cs concentrations of each local wind pattern are $564.1{\sim}1076.3Bqm^{-3}$. The highest average concentration appeared P4-4 due to dispersion in a narrow zone and weak wind environment. On the other hands, the lowest average concentration appeared P1 and P2 due to rapid dispersion to the sea. The simulated $^{137}Cs$ concentrations and dispersion locations of each local wind pattern are different according to the local wind conditions.

• Journal of Agricultural Extension & Community Development
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• v.3 no.1
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• pp.141-155
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• 1996

The purpose of this study was to investigate the sole of local newspaper for community development in Korea. Specific objectives of the study were : 1) to identify the role of local newspaper in community development, 2) to analyze problems and situations on local newspapers in Korea, and 3) to suggest desirable roles of local newspaper for the community development. To attain the above objectives, this study was carried out through literature review, contest analysis of selected local newspapers, and the questionnaire survey of selected readers of local newspaper. The data were collected from 267 readers of local newspaper who participated in the farmers` training session in the Rural Development Administration, by using questionnaires developed by the researcher, and total of 263 questionnaires were analyzed. The statistical techniques used for the study were frequence, percentile, standard deviation utilizing the $SPSS/PC^+$. The major findings of the study were as follows : 1. The major roles of functions of local newspapers identified in this study were summarized as to reinforce the community consciousness, to form community opinion, to watch and to monitor community environment, to provide education and entertainment, and to contribute to the conveyance and promotion of community culture. 2. The general characteristic of local newspaper readers surveyed were; a) average distance from town to their village was 9.3 Km, b) average age was 29 years, c) about 75% of them were senior high school graduates, and d) about 96% of them participated in group activities. 3. About 45% of the respondents used television or radio for their moor sources of local news were TV or radio, while about 31% respondents used immunity newspaper for their moor sources of local news. About 67% of the respondents kept their readership over two years, and about 40% of them read community newspaper regularly at their home. 4. The results of content analysis showed drat the local newspapers were dealing with articles on cultural affairs, community consciousness, administrative and civic affairs, however, there were not enough educational news, and various kinds of general news in the community. 5. Survey also showed the most needed news were ; 1) political news including administrative and civic affairs, 2) economic news including sales and distribution, 3) social news including social problems on environmental pollution and community development works, 4) educational news including technology and information, 5) cultural news including guide to cultural and historical sites and local brief news. 6. In the evaluation of local newspaper, the readers were generally positive in valued roles of local newspaper in community relations, community development, promoting community cohesion and understanding of community members, and about 40% of the respondents were positive in predicting the bright future perspectives of local newspapers. 7. In the readers` evaluation of local newspaper, readers responded that local newspapers were very closely related to the community and residents, reflecting the current concerns of local population and recognizing the value of community media, and the contents of local newspaper were positively related to daily lives of community residents and opinions of overall community.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.15 no.1
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• pp.1-17
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• 2011

A new method for option pricing based on the trinomial tree method is introduced. The new method calculates the local average of option prices around a node at each time, instead of computing prices at each node of the trinomial tree. Local averaging has a smoothing effect to reduce oscillations of the tree method and to speed up the convergence. The option price and the hedging parameters are then obtained by the compact scheme and the Richardson extrapolation. Computational results for the valuation of European and American vanilla and barrier options show superiority of the proposed scheme to several existing tree methods.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.183-186
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• 2001

In this paper, we first propose new texture features, BVLC (block variation of local correlation coefficients) moments, for content-based image retrieval (CBIR) and then present an image retrieval method based on the fusion of BDIP and BVLC moments. BDIP uses the local probabilities in image blocks to extract valley and edges well. BVLC uses the variations of local correlation coefficients in images blocks to measure texture smoothness well. In order not to be affected with the movement, rotation, and size of an object, the first and second moments of BDIP and BVLC are used for CBIR. Corel DB and Vistex DB are used to evaluate the performance of the proposed retrieval method. Experimental results show that the presented retrieval method yields average 12% better performance than the method using only BDIP or BVLC moments and average 13% better performance than the method using wavelet moments.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.612-615
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• 2003

The error diffusion is a good method to reconstruct the continuous tones of an image to the bilevel tones However the reconstruction of edge characteristic by the nor diffusion is represented work when power spectrum is analyzed fer display error. In this paper, we present an edge enhanced error diffusion method to preprocess original image to achieve the enhancement for the edge characteristic. The preprocessing algorithm consist of two processes. First the difference value between the current pixel and the local average of the surrounding pixel in original image is obtained. Second, the weighting function is composed by the magnitude and the sign of the local average. To confirm the effect of the proposed method, it is compared with the conventional edge enhanced error diffusion methods by measuring the radially averaged power spectrum densities (RAPSDs) for their display errors. The comparison result demonstrate the superiority of the proposed method over the conventional ones.