• Journal of the Korean Association of Geographic Information Studies
• /
• v.15 no.3
• /
• pp.13-22
• /
• 2012

The spatial structure analysis using the existing space syntax has a weakness only to apply the road factor. Hence, it is necessary to perform a new spatial structure analysis considering the regional characteristics factor as well as the road factor. The purpose of this study is to propose a modified spatial structure analysis which adopts road and regional characteristics factors using the existing space syntax and GIS and then to apply it to the spatial structure analysis of the urbanized areas in Hapdeok town. For the new analysis, the experts' survey has been conducted to derive the spatial structure factors of the area and their relative weights. Specifically, it drew the road factor as well as the regional characteristics factors such as road, district, land value, and building density. This study shows that the existing spatial structure analysis considering only the road factor does not reflect the actual spatial structure but the modified spatial structure analysis considering the road factor and the regional characteristics factors more accurately analyzes the spatial structure of Hapdeok town. Hapdeok is not an area where road networks were developed along main development axis and its centrality was changed, but an area where road networks were developed by effectiveness and equity and its centrality was changed by downtown decline. The towns like Hapdeok is more suitable for applying the modified spatial structure analysis method considering the regional characteristics factors. Further research is required for selecting characteristics factors and appropriate parameters in the modified spatial structure analysis. Further case studies await in other cities for conducting its verification.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.14 no.2
• /
• pp.162-169
• /
• 2011

Land information is the real-time spatial thing which must be considered with spatial and time factors. This study aims to apply and implement an appropriate spatiotemporal model for land information by exploring spatiotemporal data models which have been suggested in the previous studies. The implemented spatiotemporal model in this study is characterized by time and attribute. In the time aspect, it is divided by valid time and transaction time, and in the attribute aspect, includes the related information such as area and ownership. At the spatial point of view, the model has a spaghetti information structure as reducing information overlapped by managing the spatial information coordinates. The spatiotemporal land information model in this study facilitates representing the quality of attribute, spatial and time information.

• Animal Systematics, Evolution and Diversity
• /
• v.28 no.4
• /
• pp.279-290
• /
• 2012

Plecoglossus altivelis (ayu) is an amphidromous fish widely distributed in Northeastern Asia from the East China Sea to the northern Japanese coastal waters, encompassing the Korean Peninsula within its range. The shore lines of northeastern region in Asia have severely fluctuated following glaciations in the Quaternary. In the present study, we investigate the population genetic structure and historical demographic change of P. altivelis at a population level in East Asia. Analysis of molecular variance (AMOVA) based on 244 mitochondrial control region DNA sequences clearly showed that as the sampling scope extended to a larger geographic area, genetic differentiation began to become significant, particularly among Northeastern populations. A series of hierarchical AMOVA could detect the genetic relationship of three closely located islands between Korea and Japan that might have been tightly connected by the regional Tsushima current. Neutrality and mismatch distribution analyses revealed a strong signature of a recent population expansion of P. altivelis in East Asia, estimated at 126 to 391 thousand years ago during the late Pleistocene. Therefore it suggests that the present population of P. altivelis traces back to its approximate demographic change long before the last glacial maximum. This contrasts our a priori expectation that the most recent glacial event might have the most crucial effect on the present day demography of marine organisms through bottleneck and subsequent increase of effective population size in this region.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.5 no.4
• /
• pp.1-8
• /
• 2002

Comparison between the Tropical Rainfall Measuring Mission(TRMM)/Precipitation Radar(PR) and the C-band doppler radar at Cheju, Kunsan and Pusan, operated by the Korean Meteorological Administration (KMA), is conducted for validation of the surface precipitation structure, and for calibration of KMA radar instrument. Data used in validation was selected for seven rain events in the south region of about $36^{\circ}N$ and at TRMM overflight in Korea, during the summer season of 2000. Quantitatively comparing radar reflectivities from two different platforms that have different view angles, bandwidths and frequencies is a challenging task. For the comparison, the precipitation patterns are projected on the same area for TRMM PR. Through the comparison, it is realized that the reflectivity from ground-based radar is under estimated, compared to TRMM/PR observations. We discuss that is underestimation may be produced by many factors(system performance, topography, etc).

• Journal of the Korean Association of Geographic Information Studies
• /
• v.24 no.4
• /
• pp.1-25
• /
• 2021

In order to respond and prevent underground safety accidents, the Korean government has been preparing a submitting completion drawing web system project for converting the current manual-based 3D Underground Geospatial Map construction and its update system to an automation-based 3D underground information construction. However, research on standard drawings required for the automatic update of 3D underground structures is insufficient, so detailed research is needed. In this research paper, a standard map-based 3D underground structure construction plan was presented for the six types of underground structures constituting the 3D Underground Geospatial Map, enabling rapid and accurate drawing data creation and systematically 3D underground structure drawing data could be managed. In addition, we developed a 3D construction drawing tool that can be used in underground information practice so that ordinary CAD program users can easily produce processing drawings. The results derived from this paper are expected to be major reference materials for the establishment of standard frameworks and practical application guidelines for the construction of 3D underground structures in the future.

• Journal of Korean Society of Forest Science
• /
• v.102 no.1
• /
• pp.122-128
• /
• 2013

Genetic diversity and population genetic structure were estimated in nine natural populations of Exochorda serratifolia in South Korea using ISSR marker system. Average of polymorphic loci per primer was 5.8 (S.D.=2.32) and percentage of polymorphic loci per population was 78.7% with total 35 loci from 6 ISSR primers. In AMOVA, 27.8% of total genetic variation came from genetic difference among populations and 72.2% was resulted from difference among individual trees within populations. Genetic differentiations by Bayesian inference were 0.249 of ${\theta}^{11}$ and 0.227 of $G_{ST}$. Inbreeding coefficient for total populations was 0.412. There was significant correlation between genetic distance and geographic distance among populations. On the results of Bayesian cluster analysis, nine populations were assigned into three groups. The first group included 5 populations, and the second and the third had two populations per group, respectively. These three regions could explain 10.0% of total genetic variation from hierarchical AMOVA, and the levels of among-population and among-individual were explained 19.7% and 70.3%, respectively. The geographic distribution of populations following the three Bayesian clusters could be explained with mountain range as Baekdudaegan which is the main chain of mountains in Korea. The mountains as the physical barrier might hamper gene flow in the pearlbush. So when protected areas are designated for conservation of this species, we should consider those three regions into considerations and would better to choose at least one population per region.

• Mycobiology
• /
• v.45 no.3
• /
• pp.150-159
• /
• 2017

This study analyzed the distribution of endophytic fungi in 3 coastal environments with different climatic, geographical, and geological characteristics: the volcanic islands of Dokdo, the East Sea, and the West Sea of Korea. The isolated fungal endophytes were characterized and analyzed with respect to the characteristics of their host environments. For this purpose, we selected common native coastal halophyte communities from three regions. Molecular identification of the fungal endophytes showed clear differences among the sampling sites and halophyte host species. Isolates were also characterized by growth at specific salinities or pH gradients, with reference to previous geographical, geological, and climate studies. Unlike the East Sea or West Sea isolates, some Dokdo Islands isolates showed endurable traits with growth in high salinity, and many showed growth under extremely alkaline conditions. A smaller proportion of West Sea coast isolates tolerate compared to the East Sea or Dokdo Islands isolates. These results suggest that these unique fungal biota developed through a close interaction between the host halophyte and their environment, even within the same halophyte species. Therefore, this study proposes the application of specific fungal resources for restoring sand dunes and salt-damaged agricultural lands and industrialization of halophytic plants.

• Journal of Positioning, Navigation, and Timing
• /
• v.11 no.2
• /
• pp.83-89
• /
• 2022

For precise GNSS applications, the antenna phase center correction (PCC) is absolutely required. The PCC magnitude can reach the centimeter level with the antenna structure. In the present study, we first investigate the phase center offset (PCO) and phase center variation (PCO) of three different antenna models in two different reference frames, IGS08/igs08.atx and IGS14/igs14.atx. Clear L1 and L2 PCO differences were found between IGS08 and IGS14. In addition, the PCV showed characteristics that is dependent upon the signal direction (azimuth and elevation angle). The remarkable thing is that the changes of a Dorne Margolin choke-ring antenna model (AOAD/MT DOME) was very small in two reference frames. In order to analyze changes in positions according to different reference systems, GNSS data obtained from DAEJ, SUWN, and TSKB stations were processed by the precise point positioning (PPP) method. We suggest that an antenna PCO/PCV can affect the precise GNSS positioning on the order of several millimeters in two different reference frames.

• Animal cells and systems
• /
• v.14 no.1
• /
• pp.31-36
• /
• 2010

The pinewood nematode Bursaphelenchus xylophilus causes pine wilt disease and is a serious economic concern for the forest industry of South Korea. To achieve effective control with limited resources, it is necessary to clarify the transmission routes and mechanisms of dispersal of this organism. Highly polymorphic and easy-to-use molecular markers can be used for investigating this aspect. In this study, we evaluated the usefulness of amplified fragment length polymorphisms (AFLPs) for investigating the genetic variations of B. xylophilus and related individuals from China, Japan, and South Korea. The AFLP patterns obtained in our study were similar to the microsatellite patterns reported in a previous study; our AFLP patterns indicated high genetic variability and cryptic genetic structure, but did not indicate any peculiar geographic structure. Moreover, the genetic distances between individuals suggested that the Korean population was affected to a greater extent by the Chinese population than the Japanese population. Further, the gene flow among the related species appeared to be limited; however, there may be also the possibility of genetic introgression among species. These results confirm the usefulness of AFLPs for understanding the epidemiology of pine wilt disease, thereby contributing to the effective control of this disease.

• Journal of Korean Society of Forest Science
• /
• v.98 no.1
• /
• pp.1-7
• /
• 2009

We investigated the genetic variation and structure in Korean Arborvitae (Thuja koraiensis Nak.), by 29 examining I-SSR polymorphic loci in 84 individuals distributed among four natural populations in Korea. The level of population genetic diversity ($A_e$=1.44, P=72.42, $H_e$=0.258, S.I.=0.385) was similar to or slightly higher than that of plants with similar ecological traits and life history (Cupressaceae). Most genetic diversity was allocated among individuals within populations (${\Phi}_{ST}$=0.13). The UPGMA dendrogram based on genetic distance failed in showing decisive geographic relationship. The Mt. Bangtae population had the lowest level of genetic diversity and was the most distinctive from the other populations. Mt. Jang population which is possessed of the highest level of genetic variation and Mt. Bangtae population which is consisted of heterogeneous was considered to be a prime candidate for the conservation studies.