• ALGAE
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• v.19 no.3
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• pp.235-245
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• 2004

A study on seasonal characteristics of phytoplankton dynamics and environmental factors was carried out at four stations including Mara-do and U-do located in the western and eastern coast of Jeju Island in southern Korea from April 2003 to March 2004. Out of 101 phytoplankton species identified, 84 belong to Bacillariophyceae, 9 Dinophyceae, 6 phytoflagellates and 2 coccolithophorids, and the highest value of species diversity was observed in April. Phytoplankton was more abundant at the western coast than at the eastern coast from March to September and its highest abundance was 49.24 ${\times}$ 10$^3$ cells L$^{-1}$ at Mara-do in July. The pennate diatoms were more abundant at the western coast than at the eastern coast with the highest abundance of 38.75 ${\times}$ 10$^3$ cells L$^{-1}$ at Mara-do in July, and during this period Nitzschia longissima contributed 68.5% of the total phytoplankton abundance. Naviculaceae was more abundant at Gosan (western coast) in November when Stauroneis membranacea represented 80.1% of the abundance. Leptocylindrus dances contributed 49.4% of the abundance at U-do in November. Dinophyceae was more abundant at U-do in August. Water temperature and pH fluctuated from 11.7${^{\circ}C}$ to 27.1${^{\circ}C}$ and from 7.31 to 8.70, respectively. Water temperature of Mara-do was about 1-2${^{\circ}C}$ higher than the other stations. Salinity varied from 30.4 to 35.0 psu with the minimum in rainy season and the maximum at the end of winter. The concentration of NH$_4$-N, NO$_3$-N, NO$_2$-N, PO$_4$-P and SiO$_2$-Si ranged 0.07-6.79, 1.0-62.0, 1.0-8.0, 1.0-7.0 and 7.0-191.0 $\mu$g-at L$^{-1}$, respectively. Chlorophyll a concentrations varied from 0.10 to 1.17 $\mu$g L$^{-1}$. NH$_4$-N concentrations were high at U-do from May to December, and at Mara-do from January to February. The high concentrations of NO$_3$-N were found at Mara-do from June to September and at U-do from January to May. The effects of various physicochemical parameters on the seasonal distribution and succession of phytoplankton population suggest that there is a classical pattern of phytoplankton dynamics in Jeju coastal waters.

• Journal of the military operations research society of Korea
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• v.34 no.3
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• pp.53-66
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• 2008

Information Grid that connects Sensor Grid and Shooter Grid with network is the core infrastructure to enable the NCW concept. The U.S. DoD(Department of Defense) has developed the GIG(Global Information Grid) as the Information Grid that connects all of the DoD mission areas. Then the U.S. DoD has incrementally constructed GIG. In this respect, the case of the U.S. DoD's GIG construction refers to materializing ROK Information Grid concept. Therefore we studied the U.S. DoD's GIG construction trend and analyzed ROK's GIG construction trend. In result this paper proposes the way to develop and construct ROK's GIG.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2016.10a
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• pp.83-83
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• 2016

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2016.10a
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• pp.84-84
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• 2016

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2018.10a
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• pp.80-80
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• 2018

• Journal of the Korean Mathematical Society
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• v.37 no.4
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• pp.565-577
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• 2000

We consider regularity questions arising in the degenerate elliptic vector valued variational inequalities -div(｜▽u｜p-2∇u)$\geq$b(x, u, ∇u) with p$\in$(1, $\infty$). It is a generalization of the scalar valued inequalities, i.e., the obstacle problem. We obtain the C1,$\alpha$loc regularity for the solution u under a controllable growth condition of b(x, u, ∇u).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.5
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• pp.572-582
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• 1994

To investigate water mass structure and DO(Dissolved Oxygen) distribution in Chinhae Bay, temperature, salinity and DO were observed in the bay in summer and winter from 1990 to 1993, and two-dimensional tidal current and parameter log($H/U^3$) were computed. Shallow water fronts in the bay were formed in summer in Kaduk channel and the central part of the bay having log($H/U^3$) values of $2.0{\sim}2.5$. Oxygen deficiency at the bottom layer in summer occurred in the western and northern part of the bay with weak tidal current, where the value of log($H/U^3$) was more than about 3.5 and $M_2$ tidal current was less than about 20 cm/s. DO concentration at the bottom layer of Kaduk channel and the central channel of the bay having the strong tidal current was more than about 3.5 mg/l. The isolines of DO concentration were nearly parallel to the isovelocity, and the concentrations correlated with the frontal location. The frontal location and DO distribution were influenced by tidal range, river inflow and meteorological conditions, and also correlated with bottom slope characteristics.

• The Korean Journal of Malacology
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• v.8 no.1
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• pp.1-20
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• 1992

A study on the seasonal changes of the benthic macroinvertebrate community was performed on the intertidal rocky shores ao eastern coast of Cheju island and U-do throughout four seasons from october 1991 to August 1992. The macroinvertebrates were composed of 10 phyla, 18 classes, 39 orders, 94 families and 201 species. the number of speecies were 183 in summer, 147 in autumn, 138 in spring and 94 in winter, respectively. The total wpecies collected throuhout the study period were 193 species in U-do and 151 species in the eastern coast of Cheju Island. Nodilittorina exigua was the most dominant species in all seasons, followed by Monodonta neritoides in spring, autumn and winter, and pollicipes mitella in summer. U-do was higher in species diversity and richness and lower in evenness than the eastern coast. Species diversity and richness were higher in summer than any other seasons in lower intertidal zones. Community dominance indices, however, were significantly higher in upper intertidal zones than in lower intertidal zones.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.479.1-479.1
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• 2006

• Journal of the Korea Convergence Society
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• v.6 no.4
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• pp.243-248
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• 2015

U-Healthcare is a convergence service with medical care and IT which enables to examine, manage and maintain the patient's health any time and any place. For communication conducted in U-Healthcare service, the transmission methods are used that patient's medical checkup analysis results or emergency data are transmitted to hospital server using wireless communication method. At this moment when the attacker who executes the malicious access makes DRDoS(Distributed Reflection DoS) attack to U-Healthcare devices or BS(Base Station), various damages occur that contextual information of urgent patients are not transmitted to hospital server. In order to deal with this problem, this study suggests DRDoS attack scenario and countermeasures against DRDoS and converges with Big Data which could process large amount of packets. When the attacker attacks U-Healthcare devices or BS(Base Station), DB is interconnected and the attack is prevented if it is coincident. This study analyzes the attack method that could occur in U-Healthcare devices or BS which are remote medical service and suggests countermeasures against the security threat using Big Data.