• The Korean Journal of Quaternary Research
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• v.15 no.1
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• pp.1-12
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• 2001

The time-spatial distributional changes of fourteen warmth-tolerant plants have reconstructed by the use of the historical records of the Chosun Dynasty on the periods of 1454, 1531, 1660, 1760, 1842∼45, 1864, 1907 and 1931. Nine types of geographical distribution, and four types of temporal distribution are, respectively, recognised from fourteen warmth-tolerant plants. The most widely distributed species which occur at more than 100 counties was the persimmon. Species occurred more than 50 counties include the large bamboo, small bamboo and pomegranate. Tea plant and ramie are also commonly found species at more than 30 counties. Past geographical distribution of warmth-tolerant plants seems to be the result of both natural and anthropogenic environments.

• Journal of Wetlands Research
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• v.12 no.2
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• pp.59-65
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• 2010

Wetlands are a well known ecosystem which have high spatial-temporal heterogeneity of chemical characteristics. This high heterogeneity induces diverse biogeochemical processes, such as aerobic decomposition, denitrification, and plant productivity in wetlands. Understanding the dynamics of dissolved organic carbon (DOC) and inorganic nitrogen in wetlands is important because DOC and inorganic nitrogen are main factors controlling biological processes in wetlands. In this study, we assessed spatial distribution of DOC and inorganic nitrogen with relation to the different hydrology and vegetation in created wetlands. Both DOC and nitrate contents were significantly higher in vegetated areas than open areas. Different water levels also affected DOC contents and their quality. Average DOC contents were $0.37mg{\cdot}g^{-1}$ in deep riparian (DR) and $0.31mg{\cdot}g^{-1}$ in shallow riparian (SR). These results appeared to be related to the interaction between carbon supply by vegetation and microbial decomposition. On the other hand, inorganic nitrogen contents were not affected by water level differences. This result indicates that presence/absence of vegetation could be a more important factor than hydrology in the spatial dynamics of inorganic nitrogen. In conclusion, we observed that vegetation and hydrology differences induced spatial distribution of carbon and nitrogen which are directly related to biogeochemical processes in wetlands.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.2
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• pp.44-51
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• 2009

The main purpose of this study is to identify urban spatial structure by applying geographic information system and remote sensing data. This study identifies the urban spatial structure of non-megalopolis by analyzing the spatial distribution of population and employment in the case of Daegu metropolitan area. For this purpose, multi-temporal satellite image data (Landsat TM; 1995, 2000 and 2005) were utilized through the geographic information system. The distance-decay estimations in terms of population and employment density show that Daegu region as a whole shows monocentric urban characteristics. However, some evidences of polycentricism such as low explanation power of monocentric urban model, rises in multiple employment centers, decentralization of employment are emerging.

• Journal of The Geomorphological Association of Korea
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• v.20 no.4
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• pp.85-99
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• 2013

The objective of this paper is to analyze the spatial distribution of errors in the DEM generated using waterlines from multi-temporal remote sensing data and to assess flood vulnerability. Unlike conventional research in which only global statistics of errors have been generated, this paper tries to quantitatively analyze the spatial distribution of errors from a probabilistic viewpoint using geostatistical simulation. The initial DEM in Baramarae tidal flats was generated by corrected tidal level values and waterlines extracted from multi-temporal Landsat data in 2010s. When compared with the ground measurement height data, overall the waterline-based DEM underestimated the actual heights and local variations of the errors were observed. By applying sequential Gaussian simulation based on spatial autocorrelation of DEM errors, multiple alternative error distributions were generated. After correcting errors in the initial DEM with simulated error distributions, probabilities for flood vulnerability were estimated under the sea level rise scenarios of IPCC SERS. The error analysis methodology based on geostatistical simulation could model both uncertainties of the error assessment and error propagation problems in a probabilistic framework. Therefore, it is expected that the error analysis methodology applied in this paper will be effectively used for the probabilistic assessment of errors included in various thematic maps as well as the error assessment of waterline-based DEMs in tidal flats.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.734-743
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• 2007

The KTX station is one of special generators that produce a lot of trips caused by special land use such as university, airport, and super shopping mall. Special generators need special attention in developing travel demand models since the standard trip generation and distribution model in the conventional four-step approach do not provide reliable estimates of their travel patterns. New modeling approach, activity-based model, considering travel behavior of person, seem to be more appropriate for those special generators. Thus, this study introduces a spatial-temporal activity-based approach and how activity-based approach can be applied to estimation of travel demand at KTX stations.

• Journal of Korea Water Resources Association
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• v.38 no.5 s.154
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• pp.345-354
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• 2005

Time Domain Reflectometry (TDR) with multiplex system has been installed to configure the spatial and temporal characteristics of soil moisture at the Bumreunsa hillslope of Sulmachun Watershed. An intensive surveying was performed to build a refined digital elevation model (DEM) and flow determination algorithms with inverse surveying have been applied to establish an efficient soil moisture monitoring system. Soil moisture data were collected through intensive monitoring during 380 hrs in November of 2003. Soil moisture data shows corresponding variation characteristics of soil moisture on the upper, middle and lower parts of the hillslope which were classified from terrain analysis. Measured soil moisture data have been discussed on the context of physical process of hydrological modeling.

• Korean Chemical Engineering Research
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• v.58 no.2
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• pp.197-208
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• 2020

This study was carried out to analyze spatial and temporal incidence characteristics of scrub typhus and predict the future incidence of scrub typhus since the incidences of scrub typhus have been rapidly increased among vector-borne diseases. A maximum entropy (MaxEnt) ecological model was implemented to predict spatial distribution and incidence rate of scrub typhus using spatial data sets on environmental and social variables. Additionally, relationships between the incidence of scrub typhus and critical spatial data were analyzed. Elevation and temperature were analyzed as dominant spatial factors which influenced the growth environment of Leptotrombidium scutellare (L. scutellare) which is the primary vector of scrub typhus. A temporal number of diseases by scrub typhus was predicted by a deep neural network (DNN). The model considered the time-lagged effect of scrub typhus. The DNN-based prediction model showed that temperature, precipitation, and humidity in summer had significant influence factors on the activity of L. scutellare and the number of diseases at fall. Moreover, the DNN-based prediction model had superior performance compared to a conventional statistical prediction model. Finally, the spatial and temporal models were used under climate change scenario. The future characteristics of scrub typhus showed that the maximum incidence rate would increase by 8%, areas of the high potential of incidence rate would increase by 9%, and disease occurrence duration would expand by 2 months. The results would contribute to the disease management and prediction for the health of residents in terms of public health.

• Ocean and Polar Research
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• v.27 no.4
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• pp.359-379
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• 2005

In order to understand the spatial and temporal variations of nutrients and factors controlling their distribution in Gwangyang Bay, this study was carried out bimonthly from June 2001 to July 2003, Inorganic silicate and nitrate concentrations ranged from $0.04{\mu}M\;to\;69.5{\mu}M(avg.\;12.9{\mu}M)$, and from $0.12{\mu}M\;to\;42.2{\mu}M\;(avg.\;7.83{\mu}M)$, respectively. Silicate concentrations measured just after the typhoon were the highest with an average of $43.2{\mu}M$ at the surface layer in June 2001, whereas the highest nitrate concentration $(avg.\;37.0{\mu}M)$ was observed in the surface layer in July 2003. River runoff apparently influenced variations in silicate and nitrate concentrations (r=0.701 and 0.728, p<0.000, respectively) as well as salinity (r=-0.628, p<0.000). Phosphate concentrations ranged from $0.24{\mu}M\;to\;5.70{\mu}M\;(avg.\;1.34{\mu}M)$ and were highest at stations 5, 6, and 7, near a fertilizer plant with an average of $2.01{\mu}M$. On the basis of N/P and Si/N molar ratios, limiting nutrients have varied temporary and spatially. During 2001-2002, nitrogen was a limiting nutrient in the study area, and Phosphate was limited when a large volume of freshwater flowed into the bay. Silicate was limited when the high standing crops of phytoplankton occurred in the whole study area throughout 2003, and in the inner bay in February and August 2002. During the study period, factors controlling the distribution of nutrients might be summarized as follows; 1) inflow of freshwater by heavy rain accompanied by typhoons and frequent rainfall in summer, showing high concentrations of silicate and nitrate, 2) release of high phosphate concentrations from the fertilizer plant located in the south of Moydo to adjacent stations, 3) release of nutrients from bottom sediment, 4) magnitude of occurrence of phytoplankton standing crops.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.3
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• pp.63-75
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• 2015

As forest therapy is getting more attention than ever, it is important to organize time for activity and location based on spatio-temporal distribution of weather condition in forest. This study aimed to analyze precise spatio-temporal distribution of weather condition by installing long-term weather monitoring device in Yonghyun national natural recreation forest and using acquired weather data in order to support forest recreation and therapy activity. First, we statistically compared 4 models of semi-variogram and the results were all similar. We selected and analyzed the circular model for this study because it was presumed to be the best model for this case. We derived 128 results from the circular model and through semi-variogram, we identified seasonal and temporal distributions of temperature and humidity. Then, we used boxplot, made of partial sill level, to identify significant differences in seasonal and temporal distributions. As a result, in spring and early morning, both temperature and humidity showed equalized result. On the other hand, in summer and early afternoon, both temperature and humidity showed uneven result. In spring and early morning, changes in weather condition are shown little from spatial shifting, it is ideal to perform recreational activities and forest therapy but in summer and early afternoon, it is unadvisable to do so as the changes in weather condition could be harmful unless any other means of preparations are made. This study proposes its significance by analyzing seasonal micro-weather of single recreation forest and presenting seasonal and temporal outcomes.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.2
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• pp.59-71
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• 2014

At present, Korean one-person households have been continuously increased in spite of the reduction of total population. The increasement of one-person household has become a social and institutional issue. It is necessary to response socially and economically to not only changes of housing demand but also the disadvantaged classes such as the socially weak and single elderly household from the national level. In this respect, this research examined the spatial distribution (such as the increasing area, high-density area, and majority area) of one-person household with census data in the city of Busan. The clusters of one-person households were selected by focusing on the spatial distributions by time series changes of 2000, 2005, and 2010 and considering their housing characteristics. In terms of policy efficiency, the clusters of one-person households to be supported by priority were derived by analyzing the census data from 6066 output areas in the city of Busan. As a result, lots of one-person households of juniors were distributed around the university town, office facility, and station service area. Lots of one-person households at middle-aged class were distributed in Busan's original downtown and mountain-side road. Generalizing these characteristics, cluster analysis was conducted. As a result, one-person household dense area in Busan could be classified into four types. This research should be utilized as a counterplan for increasing the housing demand of one-person household or basic data for supporting small housing supply policies in the future.