• 한국환경과학회지
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• 제29권11호
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• pp.1141-1151
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• 2020

The impact of sound speed variability in the sea is the very important on acoustic propagation for the underwater acoustic systems. Understanding of the temporal and spatial variability of ocean sound speed in the sea around the Ieodo were obtained using oceanographic data (temperature, salinity). from the Korea Oceanographic Data Center, collected by season for 17 years. The vertical distributions of sound speed are mainly related to seasonal variations and various current such as Chinese coastal water, Yellow Sea Cold Water (YSCW), Kuroshio source water. The standard deviations show that great variations of sound speed exist in the upper layer and observation station between 16 and 18. In order to quantitatively explain the reason for sound speed variations, Empirical Orthogonal Function (EOF) analysis was performed on sound speed data at the Line 316 covering 68 cruises between 2002 and 2018. Three main modes of EOFs respectively revealed 55, 29, and 5% the total variance of sound speed. The first mode of the EOFs was associated with influence of surface heating. The second EOFs pattern shows that contributions of YSCW and surface heating. The first and second modes had seasonal and inter-annul variations.

• Asian Pacific Journal of Cancer Prevention
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• 제13권1호
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• pp.231-235
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• 2012

In order to explore the role of nutrients and bioactive related substances in colorectal cancer, we conducted a case-control in Uruguay, which is the country with the highest production of beef in the world. Six hundred and eleven (611) cases afflicted with colorectal cancer and 1,362 controls drawn from the same hospitals in the same time period were analyzed through unconditional multiple logistic regression. This base population was submitted to a principal components factor analysis and three factors were retained. They were labeled as the meat-based, plant-based, and carbohydrates patterns. They were rotated using orthogonal varimax method. The highest risk was positively associated with the meat-based pattern (OR for the highest quartile versus the lowest one 1.63, 95 % CI 1.22-2.18, P value for trend = 0.001), whereas the plant-based pattern was strongly protective (OR 0.60, 95 % CI 0.45-0.81, P value for trend <0.0001. The carbohydrates pattern was only positively associated with colon cancer risk (OR 1.46, 95 % CI 1.02-2.09). The meat-based pattern was rich in saturated fat, animal protein, cholesterol, and phosphorus, nutrients originated in red meat. Since herocyclic amines are formed in the well-done red meat through the action of amino acids and creatine, it is suggestive that this pattern could be an important etiologic agent for colorectal cancer.

• 대기
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• 제27권1호
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• pp.55-65
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• 2017

This study investigates how Eurasian snow cover in spring (March and April) is associated with Korean temperature during summer (June-July-August). Two leading modes of Eurasian snow cover variability in spring for 1979~2015 are obtained by Empirical Orthogonal Function (EOF) analysis. The first EOF mode of Eurasian snow cover is characterized by a zonally elongated pattern over the whole Eurasian region and its principal component is more correlated with Korean temperature during June. On the other hand, the second EOF mode of Eurasian snow cover is characterized by an east-west dipole-like pattern, showing positive anomalies over eastern Eurasian region and negative anomalies over western Eurasian region. This dipole-like pattern is related with Korean temperature during August. The first leading mode of Eurasian snow cover is associated with anomalous high (low) pressure over Korea (Sea of Okhotsk) during June, which might be induced by much evaporation of soil moisture in Eurasia during March. On the other hand, the second mode of Eurasian snow cover is associated with a wave train resembling with Eurasian (EU)-like pattern in relation to the Atlantic sea surface temperature forcing, leading to the anomalous high pressure over Korea during August. Understanding these two leading modes of snow cover in Eurasian continent in spring may contribute to predict Korean summer temperature.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2006년도 학술대회 1부
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• pp.161-168
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• 2006

본 연구는 공간적 정보의 청각적 제시 가능성을 확인하기 위해 머리전달함수(head-related transfer function: HRTF)를 통해 생성된 3D 사운드를 가상공간상 대상 위치의 직각형태(orthogonal pattern), 혹은 대각형태(diagonal pattern)의 조합으로 배열하여 투시장치(See-Through HMD)로 증강현실을 경험하고 있는 사용자 과제수행의 정확성을 측정하였다. 본 연구에서 실시한 실험들의 결과를 종합하면, 3D 사운드로 대상의 위치 정보를 제시할 때는 사용자로부터의 방향은 직각으로 위치시키는 정보 배열이 정확성을 확보할 수 있고, 또한 가상적 깊이를 이용하여 정보를 배열하는 것도 그 깊이를 구분할 수 있으나 정확성이 떨어짐을 확인하였다. 특히 보다 현실적인 과제 상황에서의 수행을 비교하기 위해 일차과제(primary task)를 하는 동안 제시된 청각자극 조건에서 이런 정확성의 차이가 마찬가지로 나타났다. 이런 결과를 통해 3D 사운드로 대상의 위치와 같은 공간적 정보를 제시 가능한 최적의 배열 형태를 제안하는데, 이는 어떤 패턴으로 정보를 구조화하여 제시하느냐에 따라 청각적 위치 정보 제시의 성공 여부가 결정된다는 것을 의미한다.

• 대기
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• 제20권4호
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• pp.495-503
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• 2010

Satellite data have an intrinsic problem due to a number of various physical parameters, which can have a similar effect on measured radiance. Most evaluations of satellite performance have relied on comparisons with limited spatial and temporal resolution of ground-based measurements such as soundings and in-situ measurements. In order to overcome this problem, a new way of satellite data evaluation is suggested with statistical tools such as empirical orthogonal function(EOF), and singular value decomposition(SVD). The EOF analyses with OMI and OMI HCHO over northeast Asia show that the spatial pattern show high correlation with population density. This suggests that human activity is a major source of as well as HCHO over this region. However, this analysis is contradictory to the previous finding with GOME HCHO that biogenic activity is the main driving mechanism(Fu et al., 2007). To verify the source of HCHO over this region, we performed the EOF analyses with vegetation and HCHO distribution. The results showed no coherence in the spatial and temporal pattern between two factors. Rather, the additional SVD analysis between $NO_2$ and HCHO shows consistency in spatial and temporal coherence. This outcome suggests that the anthropogenic emission is the main source of HCHO over the region. We speculate that the previous study appears to be due to low temporal and spatial resolution of GOME measurements or uncertainty in model input data.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.243-246
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• 2006

Wavelet approach is regarded as a useful methodology for geo-environment analysis with respect to spatial objects with periodicity and spatial pattern, compared to autocorrelation analysis, Fourier analysis, variogram analysis and so on. However, there are a few case studies for geo-lineament characterization with the actual geo-based information such as remotely sensed imagery and DEM. In this study, wavelet approach in the Uiseung caldera region are carried out to delineate characterization for geolineament spatial pattern. There are high possibilities of the development of radial lineaments from the centre of round crater due to the eruption of a volcano and the subsidence of a crater. We have grasped the directionality of the whole linear structures of the caldera via rose diagram, and then performed wavelet analysis on the profiles of orthogonal directions for main directions of the lineaments. The result of this study is likely to be used as a fundamental data in order to grasp the outline of caldera structure prior to the close estimation

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1991년도 추계학술대회
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• pp.25-29
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• 1991

In the field of prosthesis arm control, tile pattern classification of the EMG signal is a required basis process and also the estimation of force from col looted EMG data is another necessary duty. But unfortunately, what we've got is not real force but an EMG signal which contains the information of force. This is the reason why he estimate the force from the EMG data. In this paper, when we handle the EMG signal to estimate the force, spatial prewhitening process is applied from which the spatial correlation between the channels are removed. And after the orthogonal transformation, which is used in the force estimation process the transformed signal is inputed into the probabilistic model for pattern classification. To verify the different results of the multiple channels, SNR(signal to noire ratio) function is introduced.

• 한국자동차공학회논문집
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• 제17권1호
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• pp.176-181
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• 2009

The passenger airbag(PAB) designed for standard sized adults may induce unexpected results to children in out-of-position(OOP) postures. In this work, using MADYMO software, simulations of the OOP injury of children have been performed with respect to PAB design parameters and child dummy positions. The attention is focused on some details with respect to the injury of 3 and 6 year old children in two OOP postures. Among the various design parameters of the passenger airbag systems, four parameters are selected for the sensitivity analysis of the injury with the Taguchi method: bag folding pattern, vent hole size, position of the cover tear seam and the type of door tear seam. An optimal combination of the parameters is suggested.

• 한국환경과학회지
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• 제4권4호
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• pp.345-356
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• 1995

Examining the precipitation data collected during the period from 1960 to 1993, we found that Taegu Station represents an optimum station for explaining the interannual variations of the precipitation in Korea. Using the variations derived from Taegu, the secular trends of the precipitation in Korea have been studied. It was 삽so found that the interannual variations of summer monsoon precipitation are consistent with those of the annual precipitation. To explore the interannual variations of the summer monsoon precipitation, comparisons of the summer precipitation in Korea with that in China and Japan were made. The results of the empirical orthogonal function analysis showed that Korea, the Yangtze River and Huaihe River valley, and the south Japan are all located in the same climate system during summer. The detailed analysis was carried out on the comparison of the summer precipitation in Korea with that in the eastern part of the the mainland China. We found that the correlation pattern is similar to the East Asia/pacific pattern. The probable effects of the sea surface temperature on the precipitation in Korea were also discussed. Key Words : Precipitation in Korea, rainy seasons in East Asia, monsoon precipitation, interannual variations.

• 한국지구과학회지
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• 제30권6호
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• pp.721-733
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• 2009

북서태평양에서 발생하는 열대 저기압의 이동경로에 대한 변화패턴을 1951-2007년의 열대 저기압 경로 자료에 경험적 직교함수(Empirical Orthogonal Function, EOF)법을 적용하여 분석하였다. 북서태평양을 $5^{\circ}\times5^{\circ}$의 격자간격으로 나뉘어 연별 열대 저기압의 이동빈도를 각 격자에서의 변수로 정의하였다. 첫번째 모드는 동서성분(동경125도 기준)을, 두번째 모드는 남북성분(필리핀 동쪽해상에서 남지나해를 가로지르는 축 중심)을, 그리고 세번째 모드는 대각성분(타이완 동쪽 해상을 중심으로 동북방향과 동남방향을 축으로 하는)으로 나누어짐을 알 수 있었다. 첫번째와 두번째 모드의 주성분 시계열에서 각각 1997년과 1991년 부근을 기점으로 해서 주성분들의 부호가 교차되는 데, 이는 1990년대 이전 약 20년 동안에 남중국해 부근지역에서의 열대 저기압 이동 빈도가 동아시아 중위도 지역에서는 최근 20년 동안에 더 높았던 것과 관련성이 있는 것으로 보였다. 열대 저기압 발생의 경우, 첫번째와 두번째 모드에서 고유벡터 값이 음이고 진로가 북서태평양으로 주로 이동했던 열대 저기압은 고유벡터가 양의 값을 보였던 열대 저기압보다 더 동쪽에서 발생했던 것으로 나타났다. 이동특성에 있어 첫번째 모드는 바이칼호 남쪽에서 형성되는 기압 패턴에, 두번째 모드는 $30^{\circ}N$ 부근을 중심으로 남과 북 사이에 형성된 진동패턴에, 세번째 모드는 일본 부근에 위치한 기압패턴에 의해 열대 저기압의 이동경향이 많은 영향을 받는 것을 알 수 있었다. 또한, 해수면 온도 아노말리 값과 상관분석결과 첫번째 모드는 $Ni\tilde{n}o$-3.4 지수와 높은 음의 상관관계를 보여 ENSO의 영향을 받고 있음을 알 수 있었다.