• 한국해양학회지
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• v.23 no.3
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• pp.130-145
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• 1988

Spatial distribution and temporal variations of phytoplankton population were investigated in Ch$\check{o}$nsu Bay, the Korean western coast. Diurnal fluctuations of phytoplankton standing crop are associated with semidiurnal tidal cycle, as high concentration at low tide and low at high tide. In monthly variations of phytopolankton standing crop, the 1st peak occurrs in March and the 2nd one in August. The study area could be divided into two parts, outer bay and inner bay according to the physical and biological factors such as water temperature and salinity, and phytoplankton distribution patterns. The northern waters of the bay, however, may be affected by irregular fresh water influx through the lock of the dike. Because of the hydrographical differences among the surveyed stations, phytoplankton species succession patterns of each station have some differences. On the whole in this study area, Paralia sulcata and Skeletonema costatum are dominant species all the year round. However, except June, Paralia sulcata, a tychopelagic diatom is not dominant species at Station 6 (northern end of the bay). This seems to be caused by the fact that the waters of northern part of the bay is less turbulent than that of the outer bay. The result of principal component analysis (PCA) indicates that Ch$\check{o}$nsu Bay is normal coastal ecosystem where the environmental conditions are cycled in a year, and water temperature and nitrogenous nutrients such as nitrate, nitrite and ammonia are major factors to influence the annual cycle of environmental conditions.

• Journal of Life Science
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• v.28 no.1
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• pp.105-109
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• 2018

Biodiversity (or biological diversity) is defined as the variability of living organisms, the "diversity of life on Earth," and the complex relationships that make up ecosystems. This study aimed to investigate the spatial and temporal patterns in animal species composition and diversity at the Deukjin River, located in Hapcheon Province, Korea. The fauna community at the Deukjin River during 2016 season was identified with a total of 55 taxa, representing the following six classes: Mammalia (mammals), Actinopterygii (bony fish), Chondrichthyes (cartilaginous fish), Aves (birds), Amphibia (amphibians), Reptilia (reptiles), and invertebrates. The Berger - Parker index (BPI) for mammals varied from 0.233 (Station A) to 0.333 (Station D). The Shannon - Weaver index (H') and two diversity indexes (N1 and N2) for mammals and birds in the upper region were higher than those in the lower region. The values of ${\beta}$-diversity for animals varied from 0.229 for fish to 0.339 for invertebrates. The richness indices for animal taxa also varied among the stations and seasons. Station A showed considerably high richness in mammals, birds, and reptiles/amphibians. Although the richness indices (R1 and R2) for six animal kingdoms during the seasons were different from each other, the difference was not significant (p<0.05). The evenness indices for five animal kingdoms were different from each other, but again, the difference was not significant (p<0.05).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.27 no.2
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• pp.55-65
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• 2024

This study aimed to figure out diel activity patterns of water deer and wild boar, whose habitat is disturbed by human activity in a suburban area. Photographic data of water deer and wild boar collected by 18 camera traps from January 2021 to November 2022 was categorized into four diel periods (dawn, day, dusk, and night), and converted into frequencies per 100 CTD (Camera Trap-Days) for seasonal and spatial diel activity pattern analysis. Water deer exhibited intense nocturnality in fall, and wild boar did in fall and winter. During the fall, water deer's night-time capture rate was the highest (61.9%), and day-time photographic rate was the lowest (13.9%) among other seasons. During the fall and winter, wild boar's night-time photographic rate was relatively high (77.6%, 78.0%, respectively), and day-time photographic rate was relatively low (0.7%, 1.8%) in comparison with other seasons. In spatial diel activity analysis, both water deer and wild boar showed a tendency to avoid humans, especially near trails during day-time hours. The day-time photographic rate of water deer in trail-near group was 12.1% and trail-far group was 24.6%. The day-time photographic rate of wild boar was 3.4%, 5.7%, respectively. Because the diel activity patterns of wildlife reflect human disturbance, this study provides useful ecological information for developing appropriate management plans for the coexistence of water deer and wild boar in suburban areas.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.4
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• pp.138-150
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• 2012

The purpose of this study was to examine the regional disparity of ambulatory health care utilization considering spatio-temporal variation in South Korea during 1996-2008(precisely, in 1996, 1999, 2002, 2005, and 2008) using bayesian hierarchial spatio-temporal model. The spatial pattern uses an intrinsic gaussian conditional autoregressive (CAR) error component. Ornstein-Uhlenbeck method was applied to detect the temporal patterns. The results showed that substantial temporal-geographical variation depending on diseases exists in Korea. On the Contrary to the pattern of total outpatient utilizations, for example, the areas that chronic diseases distributed relatively high were most in rural where the proportion of elderly population was higher than in the urban. Chungcheongnam-do, Junlabuk-do, and Kyeongsangbuk-do had higher risks in hypertension, whereas arthritis was higher risk in the Kyeonggi-do, Chungcheongbuk-do, Junlanam-do, and Junlabuk-do. The results of this study suggested that the effective health intervention programmes needed to alleviate the regional variation of health care utilization. These outcomes also provided the foundation for further investigation of risk factors and interventions in these high-risk areas.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.4
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• pp.385-398
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• 2007

It was analysed that spatial and temporal change patterns of general water quality constituents were measured monthly from 2002 to 2005 in Jumunjin Harbour. The measured constituents are temperature, salinity, pH, SS and DO. Concentration difference of upper lower layer for general water quality constituents was small. Temperature and DO concentration show the clear difference at temporal concentration change pattern, but SS, pH and salinity have irregular change pattern. Also, water quality improvement effect of seawater exchange facilities and sewage treatment plants is analysed quantitatively using averaged spatial and temporal data set. From this result, it is found that effect of sewage treatment plants is small and seawater exchange facilities at zone 1 and 2 is clear concentration reduction effect to be about 26% and 16%, respectively. After sewage treatment plants operation, DO concentration reduced about 10% at inner zone of Jumunjin Harbour, the other side, after seawater exchange facilities concentration DO concentration increased about 10%. DO concentration at 2005 estimated little than that of 2002, it is concluded that a yearly change of DO concentration has about 10%.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.3
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• pp.171-180
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• 2002

The temporal and spatial distributions of phosphorus have been investigated in the Gomso Bay, Korea. TP, PIP, TOP and DIP in sediment were found 548.8mg P kg$^{-1}$ , 426.1mg P kg$^{-1}$ , 122.6mg P kg$^{-1}$ , and 0.217mg P kg$^{-1}$ , respectively with a decreasing order of PIP>TOP>DIP. Any temporal or spatial trend has not been found on the distribution of TP in the sediment, except the high TP values near the mouth of Julpo-chun. We found seasonal patterns high TOP(28.90% of TP) and low TIP(71.10% of TP) in August, but low TOP(15.63% of TP) and high TIP(84.38% of TP) in November. There were three times higher DIP concentration in August than in November. Such case is probably not only due to the enhanced supply of DIP directly from the decomposition of organic matter from overlying water in summer, but also the released phosphate from the adsorbed particulate matter such as PIP under the low pH and Eh conditions at the subsurface layers of the sediment induced by the active microbial respiration of increased organic materials in summer. Primarily, the source of phosphorous from municipal sewage strongly influenced the early stage of the distribution of all the phosphorous in the Gomso tidal flat. Notwithstanding, through the processes of diagenesis in sediment, water temperature and organic contents probably functioned as the key parameters to control the temporal distributions of TOP, TIP and DIP in the Gomso tidal flat.

• Korean Journal of Remote Sensing
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• v.35 no.6_3
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• pp.1273-1283
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• 2019

This paper proposes an advanced crop classification model that combines a procedure for weighted combination of spatial features extracted from multi-scale input images with a conventional convolutional neural network (CNN) structure. The proposed model first extracts spatial features from patches with different sizes in convolution layers, and then assigns different weights to the extracted spatial features by considering feature-specific importance using squeeze-and-excitation block sets. The novelty of the model lies in its ability to extract spatial features useful for classification and account for their relative importance. A case study of crop classification with multi-temporal Landsat-8 OLI images in Illinois, USA was carried out to evaluate the classification performance of the proposed model. The impact of patch sizes on crop classification was first assessed in a single-patch model to find useful patch sizes. The classification performance of the proposed model was then compared with those of conventional two CNN models including the single-patch model and a multi-patch model without considering feature-specific weights. From the results of comparison experiments, the proposed model could alleviate misclassification patterns by considering the spatial characteristics of different crops in the study area, achieving the best classification accuracy compared to the other models. Based on the case study results, the proposed model, which can account for the relative importance of spatial features, would be effectively applied to classification of objects with different spatial characteristics, as well as crops.

• Journal of Korean Society on Water Environment
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• v.29 no.3
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• pp.365-376
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• 2013

The purpose of this study was to evaluate effects of spatio-temporal changes in land uses and rainfall magnitude using the Soil and Water Assessment Tool (SWAT). Prior of application of the model to real-world problem, the model should be calibrated and validated properly. In most modeling approaches, the validation process is done assuming no significant changes occurring at the study watershed between calibration and validation periods, which is not proper assumption for agricultural watersheds. If simulated results obtained with calibrated parameters match observed data with higher accuracy for validation period, this does not always mean the simulated result represents rainfall-runoff, pollutant generation and transport mechanism for validation period because temporal and spatial variables and rainfall magnitude are often not the same. In this study SWAT was applied to Mandae study watershed in Korea to evaluate effects of spatio-temporal changes in landuses using 2009 and 2010 crop data for each field at the watershed. The Nash-Sutcliffe model efficiency (NSE) values for calibration and validation with either 2009 or 2010 was evaluated and the NSE value for calibration with 2009 and calibration with 2010 were compared. It was found that if there is substantial change in land use and rainfall, model calibration period should be determined to reflect those changes. Through these approaches, inherent limitation of the SWAT, which does not consider changes in land uses over the simulation period, was investigated. Also, Effects of changes in rainfall magnitude during calibration process were analyzed.

• Journal of the Korean association of regional geographers
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• v.21 no.1
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• pp.98-113
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• 2015

In this study, spatial and temporal patterns and changes in seasonal multi-day cumulative extreme precipitation events defined by maximum 1~5 days cumulative extreme precipitation observed at 61 weather stations in the Republic of Korea for the recent 40 years(1973~2012) are examined. It is demonstrated that the magnitude of multi-day cumulative extreme precipitation events is greatest in summer, while their sensitivity relative to the variations of seasonal total precipitation is greatest in fall. According to analyses of linear trends in the time series data, the most noticeable increases in the magnitude of multi-day cumulative extreme precipitation events are observable in summer with coherences amongst 1~5 days cumulative extreme precipitation events. In particular, the regions with significant increases include Gyeonggi province, western Gangwon province and Chungcheong province, and as the period for the accumulation of extreme precipitation increases from 1 day to 5 days, the regions with significantly-increasing trends are extended to the Sobaek mountain ridge. It is notable that at several scattered stations, the increases of 1~2 days cumulative extreme precipitation events are observed even in winter. It is also observed that most distinct increasing tendency of the ratio of these multi-day cumulative extreme precipitation to seasonal total precipitation appears in winter. These results indicate that proactive actions are needed for spatial and temporal changes in not only summer but also other seasonal multi-day cumulative extreme precipitation events in Korea.

• Journal of the Economic Geographical Society of Korea
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• v.9 no.3
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• pp.318-340
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• 2006

In the last decade, there has been a widespread interest in knowledge production activities as a new engine of endogeneous growth. In the knowledge-based economy, there has been a growing importance of the patent as the index of knowledge production. Much literature suggests that knowledge production activities tend to be spatially concentrated and formed the clusters in the advanced economies. The purpose of this paper is to analyze spatial-temporal patterns of knowledge production activities in Korea based on a data set of patents from 1981-2000. This paper uses spatial statistical methods and GIS to explore the spatial dimensions of knowledge production activities in Korea. Through this research, it was found that knowledge production activities were unevenly distributed. The knowledge production activity measured by patent counts is highly concentrated in a limited number of cities. The top 10 cities accounted for 68.5% of the total number of patents in the period of 1981-2000, suggesting the existence of a strong concentration of knowledge production activities in Korea. The locations of knowledge production activities by themselves represented a strong spatial autocorrelation. The concentration of knowledge production activities in Korea is spatially correlated to the concentration of adjacent neighboring cities. The location of knowledge production activities is not free from a spatial context and spillover of knowledge production activities are heavily bounded within geographic limits, forming a spatial cluster. There appear some quite a large spatial cluster around the seoul metropolitan area.