• 대기
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• 제18권4호
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• pp.475-483
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• 2008

The hourly precipitation data from 1973 to 2007 observed at 60 weather stations over Korea are used to characterize the diurnal and semidiurnal cycles of total precipitation amount, intensity and frequency and examine their spatial patterns and interannual variations. The results show that the diurnal cycle peaks in the morning (03-09LST) and the semidiurnal cycle peaks in the late afternoon (16-20LST). It is found that the spatial variations of the peak phase of diurnal or semidiurnal cycle relative to their corresponding seasonal mean cycle are considerably small (large) for total precipitation amount and intensity (frequency, respectively) in both winter and summer seasons. Also, the diurnal phase variations for individual years relative to the seasonal mean precipitation show the significant interannual variability with dominant periods of 2-5 years for all three elements of precipitation and the slightly decreasing trend in total precipitation amount and intensity. To compare the relative contributions of frequency and intensity to the diurnal and semidiurnal cycles (and their sum) of total precipitation amount, the percentage variance of each cycle of precipitation amount explained by frequency is estimated. The fractional variance accounted for by precipitation intensity is greater than that of frequency for these three cycles. All above analyses suggest that intensity plays a more important role than frequency in the diurnal variations of total precipitation amount.

• 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.

• 대한원격탐사학회지
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• 제26권4호
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• pp.421-437
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• 2010

SeaWiFS자료를 Maximum Normalized Difference Carbon Index(MNDCI) 알고리즘을 이용하여 추정된 particulate organic carbon(POC)는 장강에서 유입된 담수의 영향을 받는 동중국해에서 시/공간적 해양환경 변화를 조사하는데 사용했다. 10년 평균한 POC 농도는 (1997년-2007년) 뚜렷한 계절적 변화를 보인다. POC 경년 변화는 전체 지역 평균값과 표준편차를 이용하여 세 개의 지역으로 나누어 평균한 결과에서 1998년 이후 꾸준한 감소를 보이는 장강과는 달리 감소되는 경향이 관측되지 않았다. 자세한 POC 시/공간적인 변화를 관측하기 위하여, 2000년부터 2007년까지 여름철 (6월-9월) 자료를 선정하여 empirical orthogonal function(EOF) 분석을 실시하였다. 첫 번째 성분은 장강으로부터 유입되는 담수의 영향으로 공간적인 변화가 이루어졌다. 두 번째 성분은 장강의 유출량과는 약한 상관관계를 보이고, 공간적으로 남-북 방향의 변화가 관측되었다. 2000년부터 2003년까지 상대적으로 높은 POC 분포는 연구지역 남쪽 부분에서 나타난다. 2004년부터 2007년까지 이런 변화는 연구지역 북쪽 부분에서 관측되었다. 장기적인 변화는 방류량의 감소에 의한 영향보다는 공간적인 변화에 기인한 것으로 사료되며, 이는 현장 관측자료에서 유사한 결과를 보였다.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2003년도 공동 춘계학술대회 논문집
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• pp.297-299
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• 2003

Altimeter(Topex/Poseidon) and AVHRR(NOAA) data were used to study the variations and correlations of Sea Level(SL) and Sea Surface Temperature (SST) in the North East Asian Seas from November 1993 to May 1998. This region is influenced simultaneously to continental and oceanic climate as the border of the East Sea(Japan Sea). SL and SST have increased gradually every year because the global warming, and presented usually a strong annual variations in Kuroshio extension region with the influence of bottom topography.

• 대기
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• 제20권3호
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• pp.343-353
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• 2010

A regional wind network with complex surface conditions must be designed with sufficient space and time resolution to resolve the local circulations. In this study, the spatial variations of the wind field observed in the Seoul and Jeju regional networks were evaluated in terms of annual, seasons, and months to assess the spatial homogeneity of wind fields within the regional networks. The coherency of the wind field as a function of separation distance between stations indicated that significant coherency was sometimes not captured by the network, as inferred by low correlations between adjacent stations. A meso-velocity scale was defined in terms of the spatial variability of the wind within the network. This problem is predictably most significant with weak winds, dull prevailing wind, clear skies and significant topography. The relatively small correlations between stations imply that the wind at a given point cannot be estimated by interpolating winds from the nearest stations. For the Seoul and Jeju regional network, the meso-velocity scale has typically a same order of magnitude as the speed of the network averaged wind, revealing the large spatial variability of the Jeju network station imply topography and weather. Significant scatter in the relationship between spatial variability of the wind field and the wind speed is thought to be related to thermally-generated flows. The magnitude of the mesovelocity scale was significantly different along separation distance between stations, wind speed, intensity of prevailing wind, clear and cloudy conditions, topography. Resultant wind vectors indicate much different flow patterns along condition of contributing factors. As a result, the careful considerations on contributing factors such as prevailing wind in season, weather, and complex surface conditions with topography and land/sea contrast are required to assess the spatial variations of wind field on a regional network. The results in the spatial variation from the mesovelocity scale are useful to represent the characteristics of regional wind speed including lower surface conditions over the grid scale of large scale atmospheric model.

• Journal of the korean society of oceanography
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• 제31권4호
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• pp.207-216
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• 1996

A geochemical study of three piston cores (ST.4, ST.6 and ST.20) taken from the Northwest Pacific (eastern edge of Shikoku Basin) provides information about changes in surface water paleoproductivity and sedimentation during the last 127 kys. Paleoproductivity variations were estimated on the basis of total organic carbon content and carbonate mass accumulation rate. The paleoproductivity based on total organic carbon shows significant spatial variations between glacial and interglacial periods. During the last glacial maximum (LGM) paleoproductivity increased about 1.5 times with deglaciation decrease compared with those of the Holocene at inner side of the Shikoku Basin (ST.4 and ST.6). On the other hand, paleoproductivity at outer side of Shikoku Basin (ST.20) indicating not distinctive increase but deglaciation increase. The C/N ratios fall below 10 for cores ST.4 and ST.6, but C/N ratios between 100 ka and 80 ka in ST.20 which show around 10 or larger values suggest a predominance of marine organic carbon with some admixture of terrigenous materials. The carbonate mass accumulation rate of three cores show different patterns of calcareous record with respect to organic carbon based paleoproductivity variation. In the inner side of Shikoku Basin (ST.4 and ST.6) the carbonate mass accumulation rate decreased during last glacial maximum, and significant increase of carbonate mass accumulation rate is recognized at outer side of Shikoku Basin (ST.20). Thus, this set of data reveals that spatial paleoproductivity variations between inner and outer side of Shikoku Basin during the glacial and interglacial periods.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.831-835
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• 2006

NOAA/AVHRR data were used to analyze sea surface temperatures (SSTs) and thermal fronts (TFs) in the Korean seas. Temporal and spatial analyses were based on data from 1993 to 2000. Harmonic analysis revealed mean SST distributions of $10{\sim}25^{\circ}C$. Annual amplitudes and phases were $4{\sim}11^{\circ}C$ and $210{\sim}240^{\circ}$, respectively. Inverse distributions of annual amplitudes and phases were found for the study seas, with the exception of the East China Sea, which is affected by the Kuroshio Current. Areas with high amplitudes (large variations in SSTs) showed 'low phases' (early maximum SST); areas with low amplitudes (small variations in SSTs) had 'high phases' (late maximum SST). Empirical orthogonal function (EOF) analyses of SSTs revealed a first-mode variance of 97.6%. Annually, greater SST variations occurred closer to the continent. Temporal components of the second mode showed higher values in 1993, 1994, and 1995. These phenomena seemed to the effect of El $Ni{\tilde{n}}o$. The Sobel edge detection method (SEDM) delineated four fronts: the Subpolar Front (SPF) separating the northern and southern parts of the East Sea; the Kuroshio Front (KF) in the East China Sea, the South Sea Coastal Front (SSCF) in the South Sea, and a tidal front (TDF) in the West Sea. Thermal fronts generally occurred over steep bathymetric slopes. Annual amplitudes and phases were bounded within these frontal areas. EOF analysis of SST gradient values revealed the temporal and spatial variations in the TFs. The SPF and SSCF were most intense in March and October; the KF was most significant in March and May.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권2호
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• pp.807-824
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• 2016

In this paper, a method of mood classification based on user brainwaves is proposed for real-time application in commercial services. Unlike conventional mood analyzing systems, the proposed method focuses on classifying real-time user moods by analyzing the user's brainwaves. Applying brainwave-related research in commercial services requires two elements - robust performance and comfortable fit of. This paper proposes a filter based on Regularized Common Spatial Patterns (RCSP) and presents its use in the implementation of mood classification for a music service via a wireless consumer electroencephalography (EEG) device that has only 14 pins. Despite the use of fewer pins, the proposed system demonstrates approximately 10% point higher accuracy in mood classification, using the same dataset, compared to one of the best EEG-based mood-classification systems using a skullcap with 32 pins (EU FP7 PetaMedia project). This paper confirms the commercial viability of brainwave-based mood-classification technology. To analyze the improvements of the system, the changes of feature variations after applying RCSP filters and performance variations between users are also investigated. Furthermore, as a prototype service, this paper introduces a mood-based music list management system called MyMusicShuffler based on the proposed mood-classification method.

• 대한지리학회지
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• 제37권5호
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• pp.536-550
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• 2002

이 연구는 7년 동안의 수문, 기후, 수질자료를 이용하여 펜실바니아 38개 유역 수질의 공간적 변이 패턴을 고찰하였다. 연구기간동안 도시적, 농업적 토지이용이 많은 유역에서 농도의 변이가 심하게 나타났다. 질소의 농도는 농업적 토지이용과. 인의 농도는 도시적 토지이용과 상관관계가 높게 나타났다. 주성분분석을 통해 이들의 농도 변이를 설명하는 주요 성분 셋이 - 토지 지형관련, 기후관련, 규모 - 도출되었다. 부분 여분 분석을 통해 기후, 토지, 지형의 복합적인 영향이 질소 농도 변이의 28.1%를 설명하고 있으며, 순수한 토지 변수의 영향이 인 농도의 41.8 o/o를 설명하고 있음을 알 수 있었다. 주 전체적인 차원에서 농도변이의 뚜렷한 지리적 패턴-북서부지역의 낮은 농도와 남동부지역의 높은 농도-이 나타나고 있으며, 이는 지역적 규모에서 수문, 기후, 토지이용, 지형 등 여러 가지 환경변수의 복합적인 상호관련성을 반영하고 있다.

• 도시과학
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• 제9권1호
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• pp.33-40
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• 2020

This research aims to analyze the determinants of apartment rents in the Seoul Metropolitan area using spatial econometrics approaches. Since spatial econometrics approaches have advantages to solve limitations of ordinary multiple regression such as spatial dependence and spatial heterogeneity. This research includes structural variables such as number of rooms and baths, neighborhood variables such as number of housing units in the apartment complex, and location variables including distances to subway stations, to traditional markets, to educational institutes, and to urban services such as parks, etc. The result shows that the accessibilities to the CBD, to subcenters, to subway station, to school, and to parks contribute to apartment rent uplift and also shows different spatial variations in rent premiums by accessibility variables. In particular, apartments located south of Han river along the Lines 2, 3, 7 and 9 have the highest rent premiums due to the accessibility to the subway.