• Economic and Environmental Geology
• /
• v.28 no.4
• /
• pp.395-404
• /
• 1995

The geologic structure of the Cheju volcanic island has been investigated by analyzing the gravity and magnetic data. Bouguer gravity map shows apparent circular low anomalies at the central volacanic edifice, and the maximum difference of the anomaly values on the island appears to be 30 mgal. The subsurface structure of the island is modeled by three-dimensional depth inversion of gravity data by assuming the model consists of a stacked grid of rectangular prisms of volcanic rocks bounded below by basement rocks. The gravity modeling reveals that the interface between upper volvanic rocks and underlying basement warps downward under Mt. Halla with the maximum depth of 5 km. Magnetic data involve aeromagnetic and surface magnetic survey data. Both magnetic anomaly maps show characteristic features which resemble the typical pattern of total magnetic anomalies caused by a magnetic body magnetized in the direction of the geomagnetic field in the middle latitude region, though details of two maps are somewhat different. The reduced-to-pole magnetic anomaly maps reveal that main magnetic sources in the island are rift zones and the Halla volcanic edifice. The apparent magnetic boundaries inferred by the method of Cordell and Grauch (1985) are relatively well matched with known geologic boundaries such as that of Pyosunri basalt and Sihungri basalt which form the latest erupted masses. Inversion of aeromagnetic data was conducted with two variables: depth and susceptibility. The inversion results show high susceptibility bodies in rift zones along the long axis of the island, and at the central volcano. Depths to the basement are 1.5~3 km under the major axis, 1~1.5 km under the lava plateau and culminates at about 5 km under Mt. Halla. The prominent anomalies showing N-S trending appear in the eastern part of both gravity and magnetic maps. It is speculated that this trend may be associated with an undefined fault developed across the rift zones.

• Journal of Wetlands Research
• /
• v.12 no.3
• /
• pp.49-56
• /
• 2010

Euryale ferox is only annual hydrophyte among endangered plants in Korea and its seed is high valuable medicinal material. This studies were carried to find out key factors that made E. ferox endanger in Korea and to apply the results for effective management of the natural wetlands inhabited by E. ferox. We investigated the distributed sites reported by previous studies and classified the distribution-affected factors into three categories, eutrophication(hypothesis 1), soil accumulation(hypothesis 2) and increasing of water level(hypothesis 3) in the habitat. These three hypotheses were tested in the field and explained the results with the morphological characteristics of seed germination stages of E. ferox. The geographical distribution ranges of E. ferox diminished at a rate of $1^{\circ}$ latitude with about 10 natural wetlands for last 30 years. Water eutrophication in the wetland had a positive effect on the establishment of E. ferox. But higher in soil accumulation and water depth, then lower in the establishment rate of E. ferox. These results indicate that water depth in the wetland must be below 50cm during the germination season, especially in May and emergent hydrophytes filter zone is need to protect soil accumulation from soil erosion within its watershed for the effective management of wetland with E. ferox.

• Korean Journal of Microbiology
• /
• v.52 no.3
• /
• pp.365-374
• /
• 2016

In high-latitude regions, temperature has risen ($0.6^{\circ}C$ per decade) and this leads to the increase in microbial degradability against soil organic carbon (SOC). Furthermore, the decomposed SOC is converted into green-house gases ($CO_2$ and $CH_4$) and their release could further increase the rate of climate change. Thus, understanding the microbial diversity and their functions linked with SOC degradation in soil-thawing model is necessary. In this study, we divided tundra soil from Council, Alaska into two depth regions (30-40 cm and 50-60 cm of depth, designated as SPF and PF, respectively) and incubated that for 108 days at $0^{\circ}C$. A total of 111,804 reads were obtained through a pyrosequencing-based metagenomic study during the microcosm experiments, and 574-1,128 of bacterial operational taxonomic units (OTUs) and 30-57 of archaeal OTUs were observed. Taxonomic analysis showed that the distribution of bacterial taxa was significantly different between two samples. In detail, the relative abundance of phyla Actinobacteria and Firmicutes largely increased in SPF and PF soil, respectively, while phyla Crenarchaeota was increased in both soil samples. Weight measurement and gel permeation chromatography of the SOC extracts demonstrated that polymerization of humic acids, main component of SOC, occurred during the microcosm experiments. Taken together our results indicate that these bacterial and archaeal phyla could play a key function in SOC degradation and utilization in cold tundra soil.

• Economic and Environmental Geology
• /
• v.35 no.5
• /
• pp.455-463
• /
• 2002

There have been few geophysical studies on the crustal structure of the continent-ocean zone around the middle eastern part of Korean peninsula, because of the lack of database in both land and ocean. The area for the study on the internal crustal structure using gravity data is bounded by the latitude of 37$^{\circ}$-38"N and longitude of 128$^{\circ}$-132$^{\circ}$E. WCA correction is applied to shipborne gravity data to integrate with gravity anomalies obtained on land. The high frequency components of the shipborne gravity data which are considered as the noise on survey track are effectively removed by means of correlating with satellite gravity data. The corrected shipborne free-air gravity anomaly is integrated with the Bouguer gravity anomaly on land under the same condition. The integrated gravity anomaly is divided into four areas for power spectrum analysis. The depths of Moho discontinuity increases gradually from inland to Ulleung basin. As the result of modeling based on power spectrum analysis, Moho discontinuity depth is about 33-35 km in the continental zone of Korea and 18-28 km at the continental margin. Such structural character is well elucidated in changing gravity data around Ulleung basin. The depths of Moho discontinuity in the southern ocean of Ulleung-island is 16--17 km, which is much lower than in the land. The result of crustal structure modeling in this study is similar to that computed by prior seismic exploration around this area.

• Korean Journal of Ecology and Environment
• /
• v.50 no.3
• /
• pp.275-285
• /
• 2017

To investigate the changes of dominant species of benthic macroinvertebrates according to the changes of temperature and precipitation, we surveyed twenty sites of the main Seomjin River in May and September in 2013 and 2014. The temperature, precipitation, water quality factors and substrate composition, which are important factors in benthos habitat environment, were collected and measured. The average temperature of the Seomjin River increased by $0.2^{\circ}C$ in 2014 compared to 2013, and the temperature increased from upstream to downstream, showing a difference of more than $3^{\circ}C$. Also, the annual cumulative precipitation (ACP) was increased toward low latitude. The temperature of Seomjin River increased more than twice in September ($21.7{\sim}24.5^{\circ}C$) after rainfall compared to May ($7.6{\sim}11.3^{\circ}C$) before rainfall, and CP (cumulative precipitation) increased about 3 times before rainfall (263 mm~287.5 mm) and after rainfall (756.3 mm~882 mm). Due to washing effect by summer precipitation, total number of species and individuals for benthic macroinvertebrates were higher in May than in September. Chironomidae sp. and Choroterpes altioculus were dominated in May, Ecdyonurus levis, Macrostemum radiatum and Choroterpes altioculus were dominated in September. As a result of correlation analysis between community indices and environment factors, it was found that there is a high correlation with boulder and sand among substrate compositions. According to the results of cluster analysis based on temperature, CP and the dominant species of benthic macroinvertebrates in Seomjin River, it was divided into two groups following temperature and CP, and the dominant species and geographical position were reflected and divided into detailed groups.

• Journal of Korean Society of Forest Science
• /
• v.102 no.1
• /
• pp.1-6
• /
• 2013

This study was conducted to investigate the variation of fruit and seed morphology among populations and among individuals within population of Sorbus commixta Hedl. distributed in Korea. Fruits collected from 42 trees in six natural populations and their six fruit and four seed characteristics were analyzed. In all characteristics, there were significant differences among populations and among individuals within populations. Especially, number of fruits per fruit-bearing branch and number of seeds per fruit showed higher values among populations in total variance component. Coefficients of variation in the number of fruits per fruit-bearing branch and seed weight are relatively high (42.0~75.3%) compared to other traits (11.9~32.1%). As a result of simple correlation analysis, the number of fruits per fruit-bearing branch showed a significant positive correlation with latitude but showed a negative correlation with longitude. According to cluster analysis, geographically close populations showed the tendency of clustering into the same group. Three principal components (PC) were deduced from principal component analysis, which explain the 87% of total variance of fruit and seed characteristics. The highest contribution was seed length and seed weight in PC1, fruit width and seed index in PC2 and fruit length and number of fruits per fruit-bearing branch in PC3.

• Korean journal of food and cookery science
• /
• v.26 no.4
• /
• pp.441-449
• /
• 2010

The objective of this study was to investigate the physicochemical characteristics of soybeans cultivated in different regions and the accompanying soybean curd properties. To produce soybeans with regional competitiveness and demonstrate the distinctiveness of the soybean product, four regions(Paju, Andong, Muju, Hadong) and four varieties of soybean(Daewonkong, Daepungkong, Seonyukong, Cheogja 2) were selected for these experiments. There was a significant difference in the isoflavone content of soybeans and soybean curds(p<0.05). Soybeans from Andong had the highest content of genistein, daidzein and total isoflavone and soybeans from Hadong had the lowest content of these compound. Fatty acid composition of soybeans demonstrated a significant difference according to region(p<0.05). In particular, soybeans grown under adverse environmental conditions, such as high temperature and low latitude, contained the highest composition of oleic acid and the lowest composition of linoleic acid and linolenic acid. Although fatty acid content of soybean curd had a third of the fatty acid concentration of soybean, the same characteristic was observed in the fatty acid composition of soybean curd. In addition, both soybean and soybean curd had more than 80% unsaturated fatty acids and 50% of the unsaturated fatty acid content was linoleic acid. In conclusion, these results demonstrate the significant difference of soybean and soybean curd originating from different regions and showed the transition of nutritional constituents from soybean to soybean curd as a function of environmental factors. Therefore, we must consider these factors when manufacturing soy products.

• KIPS Transactions on Computer and Communication Systems
• /
• v.1 no.2
• /
• pp.71-78
• /
• 2012

The digital tachograph is a device that automatically records speed and distance of a vehicle, together with the driver's activity and vehicle status at an accident. It records vehicle speed, break status, acceleration, engine RPM, longitude and latitude of GPS, accumulated distance, and so on. European Commission regulation made digital tachographs mandatory for all trucks from 2005. Republic of Korea made digital tachographs mandatory for all new business vehicles from 2011 and is widening the range of vehicles that must install digital tachographs year by year. This device is used to analyze driver's daily driving information and car accidents. Under a car accident that makes the device reliability unpredictable, it is very important to store driving information with maximum reliability for its original mission. We designed and implemented a practical digital tachograph. This paper presents a storage scheme that consists of a first storage device with small capacity at a high reliability and a second storage device with large capacity at a low cost in order to reliably records data with a hardware at a low cost. The first storage device records data in a SLC NAND flash memory in a log-structured style. We present a reverse partial scan that overcomes the slow scan time of log-structured storages at the boot stage. The scheme reduced the scan time of the first storage device by 1/50. In addition, our design includes a scheme that fast stores data at a moment of accident by 1/20 of data transfer time of a normal method.

• Korean Journal of Remote Sensing
• /
• v.24 no.4
• /
• pp.351-358
• /
• 2008

KOMPSAT-5 will be launched in 2010 carrying a SAR (Synthetic Aperture Radar) system to obtain high resolution images of the earth surface regardless of weather or solar condition. In this paper, the orbits of KOMPSAT-5 and the imaging modes of SAR were analyzed for radargrammetry, and the best image pairs were suggested. We set the pass number from the nearest orbit to a given ground point and selected image pairs for radargrarnmetry, with height sensitivity of parallax higher than 0.5 to achieve enough height resolution and with the value lower than 0.8 to avoid errors from geometric distortion. On the equator, for example, where the distance between two adjacent passes is fixed to 95 km, we solved the orbit geometry and found that the image pairs with the pass numbers of 3-2 and 5-3 are suitable for radargrarnmetry. As the examples with arbitrary latitude, we selected Daejeon and Sejong Antarctic stations and calculated the orbital elements by using STK software. Three image pairs (5-4, 7-5 and 8-5) were found suitable for radargrammetry at Daejeon while 10 pairs (8-6, 9-7, 10-7, 11-8, 12-8, 13-9, 14-9, 15-9, 15-10 and 15-11) at Sejong Antarctic station.

• Journal of The Geomorphological Association of Korea
• /
• v.15 no.2
• /
• pp.85-94
• /
• 2008

This study is to construe spatio-temporal characteristics of temperature in cities and changes of climatical regions in analyzing a change of Korea Peninsular climate. We used daily mean air temperature data which was collected in South and North Korea for the past 34 years from 1974 to 2007. We created temperature map of 500m resolution using Inverse Distance Weight in application with adiabatic lapse rate per month in linear relation with height and temperature. In the urbanization area, the data analyzed population in comparison with temperature changes by the year. An annual rising rate of temperature was calculated $0.0056^{\circ}C$, and the temperature was increased $2.14^{\circ}C$ from 1974 to 2107. The south climate region in Korea by the Warmth index was expanded to the middle climate region by the latitude after 1990s. A rise of urban area in mean temperature was $0.5-1.2^{\circ}C$, Seoul, metropolitan and cities which were high density of urbanization and industrialization with the population increase between 1980s and 1990s. In case of North Korea, Cities were Pyeongyang, Anju, Gaecheon, Hesan. A rise in cities areas in mean temperature has influence on vegetation, especially secondary growth such as winter buds of pine trees appears built-up area and outskirts in late Autumn. Finally, nowaday we confront diverse natural events over climatical changes, We need a long-term research to survey and analyze an index on the climatical changes to present a systematic approach and solution in the future.