• Geophysics and Geophysical Exploration
• /
• v.15 no.1
• /
• pp.8-15
• /
• 2012

To estimate the S-wave velocity structure beneath the KS31 broad-band station in Wonju, Korea, we used $H-{\kappa}$ stacking and joint inversion of receiver functions and surface-wave dispersion curves derived from 297 teleseismic events (Mw > 5.5) recorded during the period between 2002 and 2009. We thereby determined that the average depth to a nearly flat Moho is $32.4{\pm}0.5\;km$ within tens of kilometer radius of the seismic station. For the crust at this location, we estimate an average shear-wave velocity of 3.69 km/s and a ratio of P- to S-wave velocities, $V_p/V_s$, of $1.72{\pm}0.04$, as is typical for continental crust. A negative phase in the receiver functions at 1 s indicates the presence of a shearwave low velocity layer in a depth interval of 10 to 18 km in the upper crust beneath the KS31 station.

• Journal of Information Management
• /
• v.41 no.4
• /
• pp.187-204
• /
• 2010

This study shows evaluation of how much OASIS meets "the korean web content accessibility guidelines" and analysis of some of the accessibility problems and their solutions in OASIS(Oriental Medicine Advanced Searching Integrated System) which is the only web site that offers papers and project information related to Traditional Medicine in Korea. The evaluation criteria to determine if OASIS is accessible is classified into four sub items; Perceivable - if information and user interface components is presentable to users in ways they can perceive, Operable - if user interface components and navigation are operable, Understandable - if information and the operation of user interface are understandable, Robust - if content is robust enough that it can be interpreted reliably by a wide variety of user agents, including assistive technologies. Based on the measured results, OASIS has just been redesigned and implemented in more accessible and effective way. OASIS that improves web accessibility for the disabled is expected to help them study oriental medicine more easily and conveniently by providing equal access and equal opportunity to use the web.

• Korean Journal of Ecology and Environment
• /
• v.52 no.3
• /
• pp.202-209
• /
• 2019

The primary productivity and production rate of photosynthetic pigment of periphyton and phytoplankton were estimated using a $^{13}C$ stable labeling technique in May 2011, in the waterfront of Lake Paldang. Primary productivity of periphyton ($28.15mgC\;m^{-2}\;d^{-1}$) was higher than phytoplankton production ($0.14mgC\;m^{-2}\;d^{-1}$). The net production rates of photosynthetic pigments(Chl a and Fucoxanthin) of periphyton were $2.53ngC\;m^{-2}\;d^{-1}$ and $0.12ngC\;m^{-2}\;d^{-1}$, respectively. On the other hand, the net production rate of pigments on phytoplankton (Chl a : $0.023ngC\;m^{-2}\;d^{-1}$, Fucoxanthin: $0.002ngC\;m^{-2}\;d^{-1}$) was lower than that of periphyton. Specific production rates of individual pigments of phytoplankton to the total primary productivity indicate the predominance of diatom (Fucoxanthin) species in phytoplankton assemblage in Lake Paldang. The net individual production rate of pigments by $^{13}C$ tracer was a useful tool to estimate the contribution of each phytoplankton class for total primary productivity, and it is possible to calculate the seasonal contribution of each phytoplankton class to the total primary productivity in the aquatic ecosystems. This study is the first report on photosynthetic pigment production rates of periphyton and phytoplankton.

• Journal of the Korean earth science society
• /
• v.42 no.1
• /
• pp.102-117
• /
• 2021

This study analyzed the learning characteristics of polar education programs operated by polar research institutes in domestic and foreign countries and aims to provide directions for improving domestic polar education programs. Using the database provided by the Korea Polar Research Institute (KOPRI), 120 programs from 16 research institutes in 9nine countries were selected. Each program was analyzed based on educational level, instructor, education period, learning place, learning environment, learning content, and learning method. Significant differences in domestic and foreign programs in terms of instructors, operational methods, educational places, and learning methods were found. Based on these findings, we discuss the direction for improving domestic polar education by expanding the base of polar education, diversifying the learning methods, and systematizing polar education using examples of actual programs. Based on the scientific, social, economic, and cultural values and importance of the polar region, this study presents specific directions to further spread and sustain polar education and culture in Korea.

• Journal of Marine Life Science
• /
• v.8 no.1
• /
• pp.43-49
• /
• 2023

This study applied a metagenomic analysis of the penguins' gut microbiome from fecal samples of Adélie Penguin (Pygoscelis adeliae) and Emperor Penguin (Aptenodytes forsteri) living along the Ross Sea, Antarctica. As a result of taxonomic analysis, 7 phyla and 18 families were mainly present in the gut microbiome of Adélie and Emperor penguins. To assess microbial diversity, we performed alpha diversity and OTU abundance analyses. It was confirmed that the Adélie Penguin's gut microbial species had a higher diversity than Emperor Penguin's. Based on the Beta diversity analysis using PCoA, differences were observed in the clustering between Adélie and Emperor penguins, respectively. Through the KEGG pathway analysis using PICRUSt, the nucleoside and nucleotide biosynthesis pathway was the most prevalent in Adélie and Emperor penguins. This study enabled a comparison and analysis of the composition and diversity of the gut microbiome in Adélie and Emperor Penguins. It could be utilized for future research related to penguin feeding habits and could serve as a foundation for analyzing the gut microbiomes of various other Antarctic organisms.

• Korean Journal of Remote Sensing
• /
• v.28 no.1
• /
• pp.11-19
• /
• 2012

Air-borne pollen, biogenically created aerosol particle, influences Earth's radiative balance, visibility impairment, and human health. The importance of pollens has resulted in numerous experimental studies aimed at characterizing their dispersion and transport, as well as health effects. There is, however, limited scientific information concerning the optical properties of airborne pollen particles contributing to total ambient aerosols. In this study, for the first time, optical characteristics of pollen such as aerosol backscattering coefficient, aerosol extinction coefficient, and depolarization ratio at 532 nm and their effect to the atmospheric aerosol were studied by lidar remotes sensing technique. Dual-Lidar observations were carried out at the Gwangju Institute of Science & Technology (GIST) located in Gwagnju, Korea ($35.15^{\circ}E$, $126.53^{\circ}N$) for a spring pollen event from 5 to 7 May 2009. The pollen concentration was measured at the rooftop of Gwangju Bohoon hospital where the building is located 1.0 km apart from lidar site by using Burkard trap sampler. During intensive observation period, high pollen concentration was detected as 1360, 2696, and $1952m^{-3}$ in 5, 6, and 7 May, and increased lidar return signal below 1.5km altitude. Pollen optical depth retrieved from depolarization ratio was 0.036, 0.021, and 0.019 in 5, 6, and 7 May, respectively. Pollen particles mainly detected in daytime resulting increased aerosol optical depth and decrease of Angstrom exponent.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.17 no.2
• /
• pp.33-44
• /
• 2012

Transparent exopolymer particles (TEP) are formed by aggregation of polysaccharide products excreted by phytoplankton and have sticky character like gel. They play important role in the production of marine snow in water column. To study the distribution pattern of TEP concentration and its role in carbon cycle in the surface ocean, we measured pH, Total alkalinity (TA), and chlorophyll-a in addition to physical characteristics of seawater within the surface water column. TEP concentrations ranged from nearly undetectable values to $338{\mu}g\;Xeq\;l^{-1}$. They were considerably lower than previously reported values from costal sites, but showed similar values observed in other oceanic region during phytoplankton bloom periods. The spatial distribution of TEP concentrations were similar to those of chlorophyll-a, which indicate that the production of TEP were closely related to phytoplankton. Calculated total dissolved inorganic carbon ($TCO_2$) from the pH and TA was normalized to 35 psu of salinity ($NTCO_2$) and showed negative linear relationship with temperature. Biological drawdown of $NTCO_2$ ($NTCO_{2bio}$) was estimated from the difference between theoretical $NTCO_2$ values and observed $NTCO_2$. In the warm region located south of $40^{\circ}N$ along the $132.5^{\circ}N$ meridional lines, $NTCO_{2bio}$ showed negative value and TEP concentrations were high. This suggested that negative $NTCO_{2bio}$ may be attributed to the biological processes. At the stations located between 44 and $46^{\circ}N$, TEP concentrations showed high concentration at the chlorophyll-a maximum layer within the water column while they showed low concentration in the surface layer. Carbon content of TEP constituted about 40% of $NTCO_{2bio}$ at the chlorophylla maximum layer. In this study, we could not observe any positive and negative relationship between TEP concentration and $NTCO_2$ or pH. It is obvious that we should consider the importance of TEP in the biological carbon cycling processes within surface layer.

• Geophysics and Geophysical Exploration
• /
• v.26 no.1
• /
• pp.18-30
• /
• 2023

Submarine mud volcanos are topographic features that resemble volcanoes, and are formed due to eruptions of fluidized or gasified sediment material. They have gained attention as a source of subsurface heat, sediment, or hydrocarbons supplied to the surface. In the continental slope of the Canadian Beaufort Sea, mud volcano exists at various water depths. The MV420, is an active mud volcano erupting at a water depth of 420 meters, and it has been the subject of extensive study. The Korea Polar Research Institute(KOPRI) collected high-resolution seismic data and heat flow data around the caldera of the mud volcano. By analyzing the multi-channel seismic data, we confirmed the reverse-polarity reflector assumed by a gas hydrate-related bottom simulating reflector(BSR). To further elucidate the relationship between the BSR and gas hydrates, as well as the thermal structure of the mud volcano, a numerical geothermal model was developed based on the steady-state heat equation. Using this model, we estimated the base of the gas hydrate stability zone and found that the BSR depth estimated by multi-channel seismic data and the bottom of the gas hydrate stability zone were in good agreement., This suggests the presence of gas hydrates, and it was determined that the depth of the gas hydrate was likely up to 50 m, depending on the distance from the mud conduit. Thus, this depth estimate slightly differs from previous studies.