• Journal of Institute of Control, Robotics and Systems
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• v.17 no.5
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• pp.460-470
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• 2011

This paper presents a dynamic workspace control method of underwater manipulator considering a floating ROV (Remotely Operated vehicle) motion caused by sea wave. This method is necessary for the underwater work required linear motion control of a manipulator's end-effector mounted on a floating ROV in undersea. In the proposed method, the motion of ROV is modeled as nonlinear first-order differential equation excluded dynamic elements. For online manipulator control achievement, we develop the position tracking method based on sensor data and EKF (Extended Kalman Filter) and the input velocity compensation method. The dynamic workspace control method is established by applying these methods to differential inverse kinematics solution. For verification of the proposed method, experimental data based test of ROV position tracking and simulation of the proposed control method are performed, which is based on the specification of the KORDI deep-sea ROV Hemire.

• Ocean and Polar Research
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• v.24 no.1
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• pp.19-31
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• 2002

Precipitation variability around King Sejong Station related with E1 $Ni\~{n}o$/Southern Oscillation (ENSO) is evaluated using the gauge-based monthly data of its neighboring stations. Though three Ant-arctic Stations of King Sejong (Korea), Frei (Chile), and Artigas (Uruguay) are all closely located within 10 km, their precipitation data show mostly insignificant positive or rather negative correlations among them in the annual, seasonal and monthly precipitation. This result indicates that there are locally large variations in the distribution of precipitation around King Sejong Station. The monthly data of Frei Station for 31 years (1970-2000) are analyzed for examining the ENSO signal in precipitation because of its longer precipitation record compared to other two stations. From the analysis of seasonal precipitation, it is seen that there is a tendency of less precipitation than the average during E1 $Ni\~{n}o$ events. This dryness is more distinct in fall to spring seasons, in which the precipitation decreases down to about 30% of seasonal mean precipitation. However, the precipitation signal related with La $Ni\~{n}a$ events is not significant. From the analysis of monthly precipitation, it is found that there is a strong negative correlation during 1980s and in the late 1990s, and a weak positive correlation in the early 1990s between normalized monthly precipitation at Frei Station and Sea Surface Temperature (SST) anomalies in the $Ni\~{n}o$ 3.4 region. However, this relation may be not applied over the region around King Sejong Station, but at only one station, Frei.

• Journal of Astronomy and Space Sciences
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• v.18 no.3
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• pp.249-256
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• 2001

KARI(Ko.ea Aerospace Research Institute) has measured the ionospheric electron temperature and density over the Korean Peninsular with the Langmuir and Electron Probe(LEP) onboard the Korean Sounding Rocket-II(KSR-II) In 1998. The purpose of LEP is to measure the electron density and temperature profile in the ionosphere. LEP consists of the Langmuir probe(LP) and the Electron temperature Probe(ETP) which are widely used for the measurement of the ionospheric plazma environment . We discuss the development of the Langmuir and Electron Probe which will be onboard the KSR-III and some test results in a simulated space plasma environment with the plasma chamber at the ISAS in Japan. These measurements could contribute to the basic study of ionospheric environment which also can be compared with other reference models such as IRI and PIM.

• Ocean and Polar Research
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• v.27 no.2
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• pp.205-214
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• 2005

From ancient Antarctic glacier ice, we extracted total genomic DNA that was suitable for prokaryotic 16S rDNA gene cloning and sequencing, and bacterial artificial chromosome (BAC) library and end-sequencing. The ice samples were from the Dry Valley region. Age dating by $^{40}Ar/^{39}Ar$ analysis on the volcanic ashes deposited in situ indicated the ice samples are minimum 100,000-300,000 yr (sample DLE) and 8 million years (sample EME) old. Further assay proved the ice survived freeze-thaw cycles or other re-working processes. EME, which was from a small lobe of the basal Taylor glacier, is the oldest known ice on Earth. Microorganisms, preserved frozen in glacier ice and isolated from the rest of the world over a geological time scale, can provide valuable data or insight for the diversity, distribution, survival strategy, and evolutionary relationships to the extant relatives. From the 16S gene cloning study, we detected no PCR amplicons with Archaea-specific primers, however we found many phylotypes belonging to Bacteria divisions, such as Actinobacteria, Acidobacteria, Proteobacteria $({\alpha},\;{\beta},\;and\;{\gamma})$, Firmicutes, and Cytophaga-Flavobacterium-Bacteroid$. BAC cloning and sequencing revealed protein codings highly identical to phenylacetic acid degradation protein paaA, chromosome segregation ATPases, or cold shock protein B of present day bacteria. Throughput sequencing of the BAC clones is underway. Viable and culturable cells were recovered from the DLE sample, and characterized by their 16S rDNA sequences. Further investigation on the survivorship and functional genes from the past should help unveil the evolution of life on Earth, or elsewhere, if any.

• Korean Journal of Environmental Biology
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• v.22
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• pp.54-62
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• 2004

We examined the impacts of anthyopogenic pollutant (benzo〔a〕pyrene) on the growth and photosynthesis of five marine phytoplankton species (Skeletonema costatum, Heterosigma akashiwo, Prorocentrum dentatum, P. minimum, Aknshiwo sanguinea), which are dominant in Korean coastal water. After the 72 h exposure to benzo〔a〕pyrene, the dramatic decrease in cell numbers was observed in the range of 1 to 10 $\mu\textrm{g}$ L$^{-1}$ for S. costatum, P. minimum, P. dentatum, whereas for A. sanguinea and H. akashiwo at the low concentrations 0.1 to 1 $\mu\textrm{g}$ L$^{-1}$ . Among the 5 phytoplankton species, the highest growth inhibition concentration ($IC_{50}$/) was 6.20 $\mu\textrm{g}$ L$^{-1}$ for P. minimum, followed by 2.14 $\mu\textrm{g}$ L$^{-1}$ for P. dentatum, 1.68 $\mu\textrm{g}$ L$^{-1}$ for S. costatum, 0.74 $\mu\textrm{g}$ L$^{-1}$ for H. akashiwo, 0.10 $\mu\textrm{g}$ L$^{-1}$ for A. sanguinea. The five species exposed to the low concentration of 1 $\mu\textrm{g}$ L$^{-1}$ were recovered after transferring to new media, but the species exposed to the high concentrations of 10 and 100 $\mu\textrm{g}$ L$^{-1}$ were not recovered, with the exception of P. minimum. Those results indicate that the thecate dinoflagellate P. minimum is most tolerant to the chemical and the athecate dinoflagellate A. sanguinea is not. Geneyally, the cell-specific photosynthetic capacity of H. akashiwo exposed to the low concentrations of 0.1 and 1 $\mu\textrm{g}$ L$^{-1}$ was higher than that of the cells in the control, whereas the cells exposed to the high concentrations of 5 and 10 $\mu\textrm{g}$ L$^{-1}$ showed the negligible photosynthetic level by the first few days of the experiment. In the case of the cells exposed to the concentration of 5 $\mu\textrm{g}$ L$^{-1}$ , after 12 days of the experiment the photosynthetic capacity was increased toward the end of the experiment. This indicates that H. akashiwo may utilize the benzo〔a〕pyrene as a carton source for its growth when exposed to low concentrations. Results suggest that anthropogenic pollutants such as benzo〔a〕pyrene may have significant influence on the succession of phytoplankton species composition and the primary production in coastal marine environments.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.4
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• pp.288-295
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• 2010

Metal exposure experiments using polychaete (Perinereis nuntia) as a bio-indicator of trace metals contamination were conducted to evaluate the bioaccumulation and the biomarkers responses such as metallothionein-like protein (MTLPs) and glutathione S-transferase (GST) which was simultaneously exposed to Cadmium (Cd) and Copper (Cu). Cu and Cd concentrations in polychaete were enhanced with increasing exposure time and their concentrations of aqueous medium. Initial accumulation of Cd was higher than that of Cu. Our results showed that the bioaccumulation of Cu and Cd were prohibited, especially at higher Cu levels, suggesting the different cellular uptake mechanisms when Cu and Cd are co-exist. Net accumulation rate of Cu was declined with exposure time but it did not show any significant change for Cd. Although the highest MTLPs concentration was observed at 6 hr of exposure time, it did not show any significant change related to exposure times and metals concentrations. An increase of GST activity tended to increase as a function of exposure time and metals concentrations. And GST activities in P. nuntia have similar tendency with bioconcentration factors in high concentration of Cu (treatment group IV) at post 24 h of exposure. Our results provide new information of the bioaccumulation and biomarker responses to understand the effects of co-existing contaminants (Cu and Cd) using polychaete. Further studies are required to elucidate the bioaccumulation and biomarkers responses for various contaminants.

• Korean Journal of Microbiology
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• v.45 no.2
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• pp.119-125
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• 2009

To understand the ecological function of heterotrophic bacterial community in water column of large freshwater lakes in the permafrost zone, we investigated the structure and function of bacterial community in Lake Khuvsgul, Mongolia. Species composition of overall bacterial community was analyzed by denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments, and bacteria that can be cultured at 10oC were isolated and characterized. Based on the depth profile of environmental parameters, thermocline and chemocline were recognized at the 5~10 m zone of the water column. The stratified DGGE profile indicated that the discontinuity of water properties might influence the structure of bacterial community: band profiles in the 0~5 m zone were diverse with large change by depth, but the profile was relatively stable at the $\geq$10 m zone, with predominance of the band identified as Acidovorax facilis. Bacterial cultures were screened for protease, cellulase, amylase and lipase activity, and 23 isolates were selected for high activity of the hydrolytic enzymes. The isolates were identified based on their 16S rRNA gene sequences. In the surface water (zero meter depth), Acidovorax defluvii and Sphingobacterium faecium with high cellulase activity were present. Flavobacterium succinicans, Mycoplana bullata and A. facilis were stably predominant isolates at 2 m, 5 m, and $\geq$10 m depths, respectively. F. succinicans isolates showed high protease activity while M. bullata isolates showed moderate levels of protease and celluase activity. A. facilis isolates showed either cellulase or lipase activity, exclusively to each other. According to the profile of growth rates of the isolates in the temperature range of $0\sim42^{\circ}C$, the surface-zone (0~5 m) isolates were facultative psychrophiles while isolates from $\geq$10 m depth were typical mesophiles. This stratification is believed to be due to stratified availability of organic materials to the bacterial decomposers. In the water column below the chemoline, the environment is extremely oligotrophic so that the trait of rapid growth in low temperature might not be demanded by deep-lake decomposers. The stratified distribution of community composition and decomposer activity in Lake Khuvsgul implies that ecological functions of bacterial community in lakes of cold region are sharply divided by water column stratification.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.9
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• pp.1348-1352
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• 2005

Most breeds of sheep in Iran are adapted to their agro ecological niches where it is likely that they were also artificially selected by their owners. In general, most of sheep breeds are multipurpose producing lambs, wool and milk. To compare the physical and chemical composition of the carcasses of ten Iranian native fat-tailed sheep breeds, 243 male lambs (6-7 months of age) of ten fattailed, Iranian breeds of sheep, Sanjabi (S), Ghezel (G), Afshari (A), Mehrabani (M), Lori (L), Lori Bakhtiari (LB), Kordi Khorasan (K), Sangesari (Sa), Baluchi (B) and Chal (C) were studied. Lamb breed group had a significant (p<0.05) effect on all the carcass traits measured. The LB and C lambs showed the same live weight which was significantly (p<0.05) higher than the other breeds. Carcass dressing- out percentage in S lambs was lowest (p<0.05), but not different from G lambs. K and Sa breeds showed the highest (p<0.05) carcass dressing-out percentage. The S lambs had the highest (p<0.05) lean meat percent. Lean meat percentage was not significantly (p>0.05) different in the G, A, M and C breeds. The Sa and K breeds showed the lowest lean meat percent. The S lambs showed the lowest (p<0.05) fat percent in their carcass, while K and Sa showed the highest (p<0.05). Subcutaneous fat in K, Sa and B was higher (p<0.05) than the other breeds. Lambs of S, G, A and M breeds had the lowest subcutaneous fat in their carcasses (p>0.05). Intramascular fat was significantly (p<0.05) lower in M, S and C despite the fact that this values were highest in B and K lambs. The K and Sa breeds had highest fat-tail percentage (p<0.05) in their carcass, whereas S and G showed lowest. Lambs of G, S and A breeds had higher bone percent than other breeds (p<0.05). Lowest bone percent (p<0.05) was seen in K and Sa lambs. The carcass moisture percent was not significantly (p>0.05) different in S, G, A, M, L and C breeds. M lambs showed the lowest crude protein percentage and S breed the highest (p<0.05). There were no significant (p>0.05) differences among other lamb breeds for this trait. Chemical fat percentage was the same in S, G, A, C and M breeds, but significantly (p<0.05) lower from LB, K, Sa and B. Ash percent in S, G and A had no significant (p>0.05) difference. According to higher lean meat and lower fat percentages in the carcass, the ranking of breeds would be S, G, A, M and C.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.4
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• pp.213-223
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• 2004

The discharges of groundwater flow were estimated using Darcy's method along the coastal zone in the Masan Bay. The estimates using the information, i.e., groundwater level, location of the observation well, hydraulic conductivity, the thickness of the aquifer, and coastline length, were 1.65% of the precipitation of the watershed. The estimated groundwater discharges through fractured rock aquifer and the aquifer with sedimentary material were $0.7\times10^4$$m^2/year$and $1.0\times10^7$$m^3/year$ respectively. Whereas, the discharge estimated by KORDI (2003) using isotopes method is about 20 times larger than the estimates from this study because of the influence of the re-circulated seawater through the coastal zone aquifer. In order to quantify this effect in detail, the groundwater levels and salinity changes in the observation wells located in the coastal zone should be continuously monitored and analyzed.

• Development and Reproduction
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• v.19 no.2
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• pp.85-96
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• 2015

Measurements of closely related sets of classical and truss dimensions were analyzed to discriminate species of scorpaenidae including the dark banded rockfish, Sebastes inermis, the black rockfish, S. schlegeli, and gobioninae including the striped shiner, Pungtungia herzi, and the slender shiner, Pseudopungtungia tenuicorpa. The measurements of the dimensions were arc sin square root transformed, and compared as a function of the standard length of each species for statistical analysis. For values of the classical dimensions of the rockfish, 6 were greater for the dark banded rockfish than for the black rockfish, 1 value was smaller for the former, and for 2 values there was no statistically significant difference (P > 0.05). For values of the classical dimensions of the shiners, 9 values were greater for the striped shiner than for the slender shiner, 2 values were smaller for the former, and for 1 value there was no statistically significant difference (P > 0.01). For values of the truss dimensions of the rockfish, 6 were greater for the dark banded rockfish than for the black rockfish, 1 was smaller for the former, and for 4 values there was no statistically significant difference (P > 0.05). For values of the truss dimensions of the shiners, 13 values were greater for the striped shiner than for the slender shiner, 3 values were smaller for the former, and for 6 values there was no statistically significant difference (P > 0.01). The dimension sets used in this study may be useful as taxonomic indicators for discriminating among fish species in Korea.