• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.203-212
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• 2012

This study aims to test presence of spatial autocorrelation of burn severity in Uljin and Youngduk areas burned in 2011. SPOT satellite images were used to compute the NDVI representing burn severity, and NDVI values were sampled for 5,000 randomly dispersed points for each site. Spatial autocorrelations of sampled NDVI values were analyzed with Moran's I and Variogram models. Moran's I values of burn severity in Uljin and Youngduk areas were 0.7745 and 0.7968, respectively, indicating presence of strong spatial autocorrelations. On the basis of Variogram and changes of Moran's I values by lag class, ideal sampling distance were proposed, which were 566-2,151 m for Uljin and 272-402 m for Youngduk. It was recommended to apply these ranges of sampling distance in flexible corresponding to Anisotropic characteristics of burned areas.

• 한국지구과학회:학술대회논문집
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• 2005.09a
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• pp.112-123
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• 2005

자기지전류 탐사의 적용에 있어 인공잡음의 영향은 탐사의 승패를 좌우하는 중요한 요소이며 인공잡음의 영향을 최소화할 수 있는 탐사의 설계와 자료처리가 요구되고 있다. 본 연구에서는 수치공간자료를 이용한 공간모델링을 통해 MT 주파수 대역에서의 잡음을 예측하고 실제 탐사 자료와 비교분석하여 MT 잡음 모델링을 가능성을 살펴보았다. 수치지도로부터 추출된 잡음원일 가능성이 높은 건물, 도로, 고압 송전선에 의해 발생하는 전자기장의 강도를 지하매질의 전기전도도에 따른 전자기파의 전파 특성을 고려하여 예측하는 잡음모델을 제안하였다. 제안된 잡음모델로부터 예측된 잡음 파워와 실제 탐사를 통해 측정된 MT 자료와의 상관도 분석을 수행한 결과, 전반적으로 전기장에서는 넓은 주파수 대역에서 높은 상관관계를 보이는 반면 자기장은 60 Hz 부근의 대역에서만 상관관계를 가진다. 본 연구에서 제안된 공간모델링을 통한 잡음 예측은 특히 고도로 산업화되어가는 도시 주변지역에서의 MT 탐사를 수행하는데 있어 유용한 정보를 제공할 수 있을 것이다.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.4
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• pp.155-162
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• 2013

The conventional block-based compressed sensing uses a fixed block size for signal reconstruction, and the reconstructed signal is degraded because the block size suitable to the signal characteristics is not used. To solve this problem, in this paper, a variable block size method for compressed sensing is proposed that estimates the signal characteristics and selects a proper block size for each frame, thereby improving the quality of the reconstructed signal. The proposed method reconstructs the signal with different block sizes, analyzes the signal characteristics using correlation coefficients for each frame, and select the block size for the frame. It is confirmed that, with the same acquired data, the proposed method reconstructs the signal of higher quality than the conventional fixed block size method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.247-250
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• 2003

This paper describes the extraction method for brain region using cellular automata from the brain MR image. In the first removing the background from the brain MR image, and then extracting the brain region by applying the cellular automata rule obtained from histogram analysis information. The results on some experimental results showed that the PSNR is 42.11(dB) on image quality and also the correlation factor is estimated 98.46%. The result of this study can be used as the auto-diagnostics system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1551-1555
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• 2003

This paper describes the extraction method for cerebro-region using cellular automata from the cerebrum MR images. The cerebro-region extracted from applying the cellular automata rules obtained from histogram distribution analysis after removing the background image from the cerebro-region by determining the critical value. The experiment results showed that PSNR is 42㏈ on the image quality and the correlation factor is estimated 98%. And the result can be used as the medical auto-diagnostics system of cerebrum.

• Geophysics and Geophysical Exploration
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• v.8 no.4
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• pp.251-261
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• 2005

The quality of MT (magnetotellurics) data highly depends on the level of artificial noise form industrial sources. We have conducted the feasibility study of MT noise modelling using digital spatial data and spatial modelling through the comparison between the predicted and the measured MT noises. A simple noise model predicting the intensity of electromagnetic field radiated from the latent noise sources, that is, the electric facilities in the building, road and high-voltage powerline, is developed in consideration of the propagation property of electromagnetic waves. From the analysis of correlation between the predicted and the measured noise power, the correlation coefficients of electric field are higher than those of magnetic field in whole frequency band. The magnetic field component has the high correlation in the narrow band near 60 Hz only. The spatial noise modelling proposed in this study would provide some useful informations for the MT surveys in the noisy environment like urban area.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.4 s.346
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• pp.31-38
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• 2006

In this paper, we propose an efficient preceding scheme for STBC-Spatial Muiltiplexing OFDM systems. In MIMO systems, the precoder is designed on the assumption that feedback channel information is perfectly known to transmitter and receiver. However, feedback delay and link errors in real environment make the transmitter use the incorrect channel information and consequently cause the performance degradation. The proposed precoder is designed to compensate for the performance degradation by the diversity gain provided by STBC. At the transmitter, the precoder for each subcarrier is constructed by using the index of codebook, subcarrier correlation, and auto correlation of channel. From the simulation results, STBC-spatial multiplexing OFDM outperforms the preceded-spatial multiplexing OFDM at $SER=10^{-3}$ when the Doppler frequency is greater than 60Hz.

• Journal of Gifted/Talented Education
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• v.20 no.2
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• pp.503-526
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• 2010

We investigated the brain activity in perceiving the emotional stimuli between a science invention group(n=13) and a general group(n=13). The science invention group, which mostly consisted of recipients of creativity prizes, scored 96% on creative personality tests(WKOPAY, SAM), whereas the general group performed at an average level on these tests. Analyzing the brain activity in perceiving the emotional stimuli(IAPS pictures), the science invention group than the general group showed higher activity in certain areas, such as MTG, STG, and so on. When correlation analysis was performed on the creative personality score and brain activity, MTG, STG, and so on areas showed significant correlations. There were more correlation areas in valence than in arousal. These results show that scientific creativity is related to emotional susceptibility. Thus, we insist that emotion be considered in the assessment and education programs for the gifted in science.

• Journal of Astronomy and Space Sciences
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• v.26 no.1
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• pp.9-24
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• 2009

We compare the relation among the annual distribution of sunspots: coronal mass ejections (CMEs) and geomagnetic storms and North-South asymmetry during solar cycle 23. For this purpose, we calculate correlation coefficients between (i) annual distribution and N-S asymmetry of CMEs - sunspots (ii) distribution of CMEs - occurrence number of geomagnetic storms (iii) distribution of sunspots - occurrence number of geomagnetic storms. We find that (i) the annual distribution of total CMEs has good correlation with distribution of annual average of sunspots but poor correlation with N-S asymmetry of sunspots, N-S asymmetry of CMEs has good correlation with N-S asymmetry of sunspots: (ii) total and N-S asymmetry of CMEs have poor correlation with occurrence number of geomagnetic storms, it's, however, well correlated with the classified groups of CMEs (Ap, Dst and an indices vs. fast CMEs($\upsilon$ > $1000kms^{-1}$), Dst index vs. Halo CMEs), and (iii) sunspot numbers and area are correlated with occurrence number of geomagnetic storms. We conclude that annual distribution of CMEs and sunspots have well correlated with geomagnetic storms, N-S asymmetry of CMEs and sunspots have poor correlated with the geomagnetic storms.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.3
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• pp.253-262
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• 2016

As a basic research to investigate geographical variations of diseases, this study analyzes and compares spatial patterns of 24 different diseases in South Korea using prevalence rate data provided by Community Health Survey in 2012. Descriptive statistical analysis, global Moran’s I computation, and disease mapping were conducted to examine spatial associations and patterns of each disease. After the unique spatial patterns and distinctive spatial associations of each disease were observed, we concluded that 12 diseases displayed statistically significant spatial autocorrelation while the other 12 showed no spatial associations. This study suggests that diseases are caused by different risk factors and possess different etiological mechanisms. Furthermore, the study may lay foundation for future studies of geographical variations of disease prevalence in South Korea.