• Journal of Preventive Medicine and Public Health
• /
• v.54 no.5
• /
• pp.301-308
• /
• 2021

Objectives: Despite its advantages, it is not yet common practice in Korea for researchers to investigate disease associations using spatio-temporal analyses. In this study, we aimed to review health-related epidemiological research using spatio-temporal analyses and to observe methodological trends. Methods: Health-related studies that applied spatial or spatio-temporal methods were identified using 2 international databases (PubMed and Embase) and 4 Korean academic databases (KoreaMed, NDSL, DBpia, and RISS). Two reviewers extracted data to review the included studies. A search for relevant keywords yielded 5919 studies. Results: Of the studies that were initially found, 150 were ultimately included based on the eligibility criteria. In terms of the research topic, 5 categories with 11 subcategories were identified: chronic diseases (n=31, 20.7%), infectious diseases (n=27, 18.0%), health-related topics (including service utilization, equity, and behavior) (n=47, 31.3%), mental health (n=15, 10.0%), and cancer (n=7, 4.7%). Compared to the period between 2000 and 2010, more studies published between 2011 and 2020 were found to use 2 or more spatial analysis techniques (35.6% of included studies), and the number of studies on mapping increased 6-fold. Conclusions: Further spatio-temporal analysis-related studies with point data are needed to provide insights and evidence to support policy decision-making for the prevention and control of infectious and chronic diseases using advances in spatial techniques.

• Journal of Environmental Science International
• /
• v.19 no.8
• /
• pp.1013-1023
• /
• 2010

The purpose of this study was to analyze the characteristics of spacio-temporal variation for $PM_{10}$ and $PM_{2.5}$ concentration in Busan. $PM_{10}$ concentration has been reduced for the past three year and exceeded $50\;{\mu}g/m^3$ of the national standard for $PM_{10}$. $PM_{2.5}$ concentration showed gradual decrease or stagnant trends and exceeded the U.S. EPA standard. Seasonal analysis of $PM_{10}$ and $PM_{2.5}$ suggested spring>winter>fall>summer(by Asian dust) and winter>spring>summerenlifall(by anthropogenic effect) in the order of high concentration, respectively. Characterization of diurnal variations suggests that $PM_{10}$ levels at all the three sites consistently exhibited a peak at 1000LST and $PM_{2.5}$ at Jangrimdong experienced the typical $PM_{2.5}$ diurnal trends such that a peak was observed in the morning and the lowest level at 1400LST. In the case of seasonal trends, the $PM_{2.5}/PM_{10}$ ratio was in the order of summer>winter>fall>spring at all the study sites, with a note that spring bears the lowest concentration. During AD events, $PM_{10}$ concentration exhibited the highest level at Jangrimdong and the lowest level at Joadong. And $PM_{2.5}/PM_{10}$ ratio in AD was 0.16~0.28.

• Journal of the Korean earth science society
• /
• v.26 no.3
• /
• pp.199-217
• /
• 2005

Using monthly total ozone data obtained from a Total Ozone Mapping Spectrometer (TOMS) onboard the Nimbus-7 and Earth Probe satellite, this study examined the trend in the total amount of global ozone during two periods: from 1979-1992 [Early period] and 1997-2002 [Latter period]. The Annual average of total ozone during the Early period was globally reduced by about 10 DU compared to the amount during the Latter, except in some areas between the equator and 20 N. Global trends of total ozone showed a decrease of -6.30 DU/decade during 1979-1992, and an increase of 0.12 DU/decade during 1997-2002. Its enhancement during the Latter period was especially noticeable in tropical areas. The EOF analyses of total ozone from this period indicated signs of temporal/spatial variability, associated with the phenomena of Quasi-Biennial Oscillation (QBO), Quasi-Triennial Oscillation (QTO), El Nino Southern Oscillation (ENSO), and volcanic eruption. Seasonal profiles of tropospheric ozone in the tropics obtained from ozonesondes, showed the spatial pattern of zonal wavenumber one. Overall, this study may be useful in analyzing possible causes in the variations of statospheric and tropospheric ozone.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.314-314
• /
• 2023

Extreme climate events can have a large impact on human life by hampering social, environmental, and economic development. Global circulation models (GCMs) are the widely used numerical models to understand the anticipated future climate change. However, different GCMs can project different future climates due to structural differences, varying initial boundary conditions and assumptions about the physical phenomena. The multi-model ensemble (MME) approach can improve the uncertainties associated with the different GCM outcomes. In this study, a comprehensive rating metric was used to select the best-performing GCMs out of 11 CMIP5 and 13 CMIP6 GCMs, according to their skills in terms of four temporal and five spatial performance indices, in replicating the 21 extreme climate indices during the baseline (1975-2017) in South Korea. The MME data were derived by averaging the simulations from all selected GCMs and three top-ranked GCMs. The random forest (RF) algorithm was also used to derive the MME data from the three top-ranked GCMs. The RF-derived MME data of the three top-ranked GCMs showed the highest performance in simulating the baseline extreme climate which was subsequently used to project the future extreme climate indices under both the representative concentration pathway (RCP) and the socioeconomic concentration pathway scenarios (SSP). The extreme cold and warming indices had declining and increasing trends, respectively, and most extreme precipitation indices had increasing trends over the period 2031-2100. Compared to all scenarios, RCP8.5 showed drastic changes in future extreme climate indices. The coasts in the east, south and west had stronger warming than the rest of the country, while mountain areas in the north experienced more extreme cold. While extreme cold climatology gradually declined from north to south, extreme warming climatology continuously grew from coastal to inland and northern mountainous regions. The results showed that the socially, environmentally and agriculturally important regions of South Korea were at increased risk of facing the detrimental impacts of extreme climatology.

• Current Research on Agriculture and Life Sciences
• /
• v.32 no.3
• /
• pp.135-143
• /
• 2014

The variability and temporal trends of the annual and seasonal minimum and maximum temperature, rainfall, relative humidity, wind speed, sunshine hours, and runoff were analyzed for 5 major rivers in Korea from 1960 to 2010. A simple regression and non-parametric methods (Mann-Kendall test and Sen's estimator) were used in this study. The analysis results show that the minimum temperature ($T_{min}$) had a higher increasing trend than the maximum temperature ($T_{max}$), and the average temperature increased by about $0.03^{\circ}C\;yr.^{-1}$. The relative humidity and wind speed decreased by $0.02%\;yr^{-1}$ and $0.01m\;s^{-1}yr^{-1}$, respectively. With the exception of the Han River basin, the regression analysis and Mann-Kendall and Sen results failed to detect trends for the runoff and rainfall over the study period. Rapid land use changes were linked to the increase in the runoff in the Han River basin. The sensitivity of the evapotranspiration and ultimately the runoff to the meteorological variables was in the order of relative humidity > sunshine duration > wind speed > $T_{max}$ > $T_{min}$. Future studies should investigate the interaction of the variables analyzed herein, and their relative contributions to the runoff trends.

• Journal of the Korean association of regional geographers
• /
• v.18 no.4
• /
• pp.414-432
• /
• 2012

Land price is a kind of text to read urban spatial structure. The purpose of this paper is to inquire into the characteristics of Daegu's urban structure and its change in time through exploring spatio-temporal variations of land price with a detailed spatial and temporal resolution. To achieve this, land value surfaces were represented using the officially assessed land price every other year from 1995 to 2011. Through mapping and exploring spatio-temporal patterns and fluctuation rates of land price for this period, changes in urban structure, the effects of local decision makings such as Greenbelt adjustment, housing site development, and gentrification, and the effects of business fluctuations or policies at global or national scales could be caught. In addition, the trends for suburbanization and multi-centric urban form could be examined from the results of a negative exponential model explaining the effect of distance from an urban center on spatial variation of land price. These results demonstrate that urban analysis using land price mirroring spatial decision making at various scales could deepen understanding for internal structure and change of a city and provide useful information for establishing regional and urban development policies and evaluating their effects.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.53 no.3
• /
• pp.1-11
• /
• 2011

The temporal variability of spring (March, April, May) monthly precipitation, precipitation effectiveness, monthly maximum precipitation, monthly precipitation of different durations, and the precipitation days over several threshold (i.e. 0, 10, 20, 30, 40, and 50 mm/day) of 59 weather stations between 1973 and 2009 were analyzed. Also to analyze the regional characteristics of temporal variability, 59 weather stations were classified by elevations, latitudes, longitudes, river basins, inland or shore (east sea, south sea, west sea) area and the level of urbanization. Results demonstrated that trends of variables increase in April and decrease in May except precipitation day. Overall trend of precipitation amount and precipitation effectiveness is same but precipitation effectiveness of several sites decrease despite the trend of precipitation amount increases which may be caused by the air temperature increase. Therefore more effective water supply strategy is essential for Spring season. Regional characteristics of Spring precipitation variability can be summarized that increase trend during May become stronger with the increase of latitude and elevation which is similar to that of Summer season. The temporal variability of variables showed different behaviors according to river basins, inland or shore (east sea, south sea, west sea) area and the level of urbanization.

• Electronics and Telecommunications Trends
• /
• v.8 no.2
• /
• pp.69-91
• /
• 1993

In the conventional speech processing, the technique of FFT(Fast Fourier Transform) is usually applied to the finite number of samples within the window of specified length using the fixed sampling rate. In this case, the temporal resolution is dependent upon the length of window while the spectral resolution is dependent upon the number of samples within the window. Thus, once the temporal resolution is determined the spectral resolution is also determined or vice versa. To resolve this type of dilemma, a new type of bank-filter similar to the characteristics of cochlear model needs to be considered. Furthermore, wide dynamic range of cochlea certainly helps the stable extraction of speech features. In the paper, the human auditory system will be briefly introduced and previous works on auditory preprocessors based on cochlear model will be reviewed. As a conclusion, the design considerations of auditory preprocessors based on cochlear model will be addressed.

• Journal of Environmental Science International
• /
• v.9 no.6
• /
• pp.483-488
• /
• 2000

In this study, the distribution characteristics of volatile organic compounds (VOCs) were investigated on the seasonal basis across spring, summer, and fall during the year of 1998. According to this analysis, most VOC species investigated exhibited strong temporal trends. Over diurnal scale, there distribution characteristics were affected by seasonal factors strongly. While they showed high day/night ratio pattern during spring, the pattern was reversed during fall. When the seasonal mean values were compared between the two seasons, the spring values were systematically higher than their counterparts in most cases. In addition when our VOC measurement date were compared with those reported from elsewhere, we were able to conclude that the VOC levels in the study area are comparable to the level weakly impacted by the regional emissions of VOCs. Although our data are not sufficient enough to systematically explain the atmospheric distribution and behavior of VOCs, the findings of strong correlations among some of VOC species suggests strong need for investigating their interactions in the earth\`s atmosphere.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.266-268
• /
• 2003

This is based on the AGENT-LUC model framework. Luangprabang Province has the largest percentage of shifting cultivation area in Laos PDR. The model simulates the spatial and temporal patterns of the shifting cultivation in the study area, using a GIS database while the total area of shifting cultivation is controlled by supply and demand balance of food. The model simulation period is from 1990 to 1999, at a spatial resolution of 500m. The results are evaluated using statistical data and remote sensing images. Through the validation, it is concluded that the trends simulated agrees to that of statistical data and the spatial and temporal patterns are also replicated satisfactorily.