• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.23 no.6
• /
• pp.475-483
• /
• 1990

An assessment of Kuwait's commercial fish stocks: hamoor (Epinephelus tauvina), zobaidy (Pampus argenteus), nakroor (Pomadasys argenteus) and sheiry (Lethrinus nebulosus), was conducted using length-frequency data, mean growth and mortality estimates obtained during 1981$\~$1988. The length-cohort analysis indicated that increases in fishing effort would not lead to long-term gains in yield of the stocks at the current estimate of natural mortality rate (M). At high M which was assumed arbitrarily, some benefit in yield could be obtained, especially for hamoor and sheiry. At low M, the yield of all stocks decreased with increased fishing effort. Increases in fishing effort resulted in significant dec-line in spawning stock size for all the stocks. Yield-per-recruit analysis indicated that, un-der low M assumption, a higher yield can be obtained for zobaidy and nakroor by reducing fishing effort. At moderate M, decreases in fishing effort brought gains in yield per recruit of the stocks, but it was not substantial compared with the present level of M. At high M, most of the stocks reached the maximum yield-per-recruit. Overall, increased fishing effort either will not be associated with large long-term gains in yield or, in some stocks, might cause a decline from the present level.

• Journal of The Geomorphological Association of Korea
• /
• v.26 no.2
• /
• pp.55-67
• /
• 2019

This study tries to reveal and compare uplift rates in the southern coast of the Korean Peninsula, based on absolute ages from coastal terrace on the coast. The uplift rate in the East Coast from previous study ranges from 0.258 to 0.357 m/ka with a median rate of 0.262 m/ka and shows an increase trend from north to south. Median uplift rate of 0.082 m/ka with minimum and maximum rates of 0.053 m/ka and 0.127 m/ka, respectively, is calculated in the South Coast from previous and this studies. The uplift rate in the West Coast from 3 absolute ages in this study is 0.082~0.112 m/ka with a median rate of 0.090 m/ka. Based on these uplift rates in the southern coast of the Korean Peninsula, it can be concluded that since MIS 5, the East Coast has experienced 3 to 4 times faster uplift rate than the West and South Coasts. However, this study suggests that more discussion on whether these uplift rates are long-term tectonic movement associated with tilted warping movement since the Tertiary or short-term tectonic movement associated with isostatic rebound due to sea level change since the Last Interglacial is needed.

• Clinical and Experimental Pediatrics
• /
• v.46 no.9
• /
• pp.865-870
• /
• 2003

Purpose : We measured the umbilical cord arterial concentrations of isoprostane($8-iso-PGF_{2{\alpha}}$) and intended to decide whether the umbilical cord arterial concentrations of isoprostane could be used as a useful parameter for lipid peroxidation in newborn infants. Methods : The isoprostane and malondialdehyde(MDA) concentrations of the umbilical cord were measured by enzyme immunoassay and TBARS(thiobarbituric acid reactive substance) assay in 33 preterm and 28 term infants, respectively. The concentrations of isoprostane and MDA were compared between preterm infants and term infants, and were analysed for association with perinatal risk factors and neonatal complications. Results : Umbilical cord arterial concentrations of isoprostane were $704.7{\pm}635.6pg/mL$ and $421.9{\pm}306.5pg/mL$ in preterm and term infants, respectively. Umbilical cord arterial concentrations of MDA were $44.0{\pm}22.9{\mu}M/L$ and $26.2{\pm}10.7{\mu}M/L$ in preterm and term infants, respectively. Umbilical cord arterial concentrations of isoprostane and MDA in preterm infants were significantly higher than those in term infants(P<0.05). The umbilical cord arterial concentrations of isoprostane were significantly associated with perinatal risk factors such as fetal distress, oligohydramnios, and breech delivery in preterm infants and pregnancy-induced hypertension in term infants(P<0.05). Conclusion : Umbilical cord arterial concentrations of isoprostane in preterm infants were higher than those in term infants, and those are significantly associated with some perinatal risk factors.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.9
• /
• pp.422-430
• /
• 2016

We investigated the abundance and composition of the zooplankton community around Dokdo in the East Sea from 2006 to 2015. Zooplankton samples were collected in the surface mixed layer by vertical hauls using a standard type net at the monitoring stations. There were no clear long-term trends in the average temperature and salinity, but relatively low salinity was recorded in the summer of 2013 and 2015. The average abundances of zooplankton in the summer increased by two orders of magnitude from $317inds./m^3$ in 2008 to $10,242inds./m^3$ in 2015. This long-term increase was accompanied by a slight increase in the chlorophyll-a concentration and a decrease in the catch of potential crucial predators (anchovy, mackerel pike, squid, herring and horse mackerel) in the study area. The dominant zooplankton, accounting for most of the long-term increase, consisted of appendicularian (Oikopleura spp.), which showed a steady increase since 2012, summer species such as Noctiluca scintillans and the cladoceran Penilia avirostris, which showed an abrupt increase, and the copepod Paracalanus parvus s.l., which showed a rapid increase after its first occurrence in summer 2010. These results suggest that the long-term increase of zooplankton could be related to the increase in the concentration of prey and the decrease in the predation pressure of potential predators around Dokdo in the study area.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.3
• /
• pp.48-55
• /
• 2015

This paper studies how to solve a problem caused by M2M terminals sending a few data based on $3^{rd}$ Generation Partnership Project(3GPP) Long Term Evolution-Advanced(LTE-A) system and then it is analyzed, proposed, and introduced into the techniques. Especially, it is introduced solution for the lack of Random Access Channel and an increasing number of latency caused by countless M2M devices. It is proposed the technology for M2M grouping as well as allowable access probability according to user type. As it decreases the number of terminal by grouping M2M devices to try random access at PRACH, it can be reduced collision between Cellular users and M2M devices. So, it is proved that the proposed mechanism can solve the increasing average latency of random access on system coexisting Cellular users and M2M devices through simulations.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2019.05a
• /
• pp.84-85
• /
• 2019

• The Bulletin of The Korean Astronomical Society
• /
• v.44 no.1
• /
• pp.52.3-52.3
• /
• 2019

We investigate a relative contribution from short to long-term flaring rate to predicting M and X-class flare probabilities. In this study, we consider magnetic parameters summarizing distribution and non-potentiality by Solar Dynamics Observatory/Helioseimic and Magnetic Imager and flare list by Geostationary Operational Environmental Satellites. A short-term rate is the number of major flares that occurred in an given active region (AR) within one day before the prediction time. A mid-term rate is a mean flaring rate from the AR appearance day to one day before the prediction time. A long-term rate is a rate determined from a relationship between magnetic parameter values of ARs and their flaring rates from 2010 May to 2015 April. In our model, the predicted rate is given by the combination of weighted three rates satisfying that their sum of the weights is 1. We calculate Brier skill scores (BSSs) for investigating weights of three terms giving the best prediction performance using ARs from 2015 April to 2018 April. The BSS (0.22) of the model with only long-term is higher than that with only short-term or mid-term. When short or mid-term are considered additionally, the BSSs are improved. Our model has the best performance (BSS = 0.29) when all three terms are considered, and their relative contribution from short to long-term rate are 19%, 23%, and 58%, respectively. This model seems to be more effective when predicting active solar ARs having several major flares.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.30 no.4
• /
• pp.308-316
• /
• 2024

Maintaining the appropriate number of national seafarers is essential for securing the competitiveness of maritime industry and security in Korea. However, the number of national seafarers in Korea has been decreased continuously recently. The government recognizes the repercussion of this issue and has been attempting to solve it. One of the most significant reasons contributing to the rapid decrease in national seafarers is presumed to be the high initial turnover rate due to the decreased preference for maritime careers among people in the 20s and 30s. Therefore, plans have been devised to prepare various policies that allow young people to select long-term boarding. This study analyzed the determinants of long-term boarding decisions among students enrolled in the Maritime College of 'M' University and verifies the relationship with the desired boarding period. Additionally, the crew composition (CC), long-term planning (LP), work environment (WE), and family environment (FE) were derived as the determinants of long-term boarding recognized by prospective seafarers. Among them, LP and WE significantly affect the desired boarding period, thus suggesting that the stronger the perception toward long-term planning and the more insensitive one is to the work environment, the longer is the desired boarding period. In terms of group differences in the perception of long-term boarding, analysis results show that the several determinants of long-term boarding are recognized differently depending on gender. This study may facilitate the preparation of factors and group-specific policy measures to promote long-term boarding among prospective seafarers.

• Journal of Environmental Science International
• /
• v.21 no.2
• /
• pp.125-133
• /
• 2012

Climatological trend for the period of 1970 to 2009 in sea water temperature around the Antarctic Peninsular waters in the Southern Ocean was investigated. During the period from 1970 to 2009, sea water temperature in the top 500 m water column except 100 m increased at a rate of $0.003-0.011^{\circ}C{\cdot}yr^{-1}$, but at 100 m it decreased at a rate of $-0.003^{\circ}C{\cdot}yr^{-1}$. Although long-term trend is generally warming, there were several periods of sharp changes between 1970 and 2009. Annual mean sea water temperature between surface and 500 m except 100 m decreased from the early of 1970s to the end of 1980s, and then it increased to the end of 2000s. In the entire water column between the surface and 500 m, sea water temperature closely correlated with the El Nino events expressed as the Southern Oscillation Index(SOI), and SOI and sea water temperature have a dominant period of about 3-5 years and decade.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.09a
• /
• pp.59-62
• /
• 2004

Hydraulic conductivity tests were conducted on a geosynthetic clay liner (GCL) for more than 2.5 yr using inorganic salt solutions to evaluate how the long-term hydraulic conductivity is affected by cation concentration and valence. Only small changes (i.e., $\leq$ 2X) in hydraulic conductivity (K) occurred during the test duration when the permeant solution was deionized (DI) water or 100 mM KCl and NaCl solutions. For weak CaCl$_2$ solutions ($\leq$ 20 mM), the hydraulic conductivities initially (< 0.2 yr) were comparable to the hydraulic conductivity obtained with DI water, but gradually increased by a factor of 2 to 13 over a period of nearly 2 yr. In contrast, the GCL permeated with strong CaCl$_2$ solutions ($\geq$ 50 mM) reached equilibrium nearly immediately, with a hydraulic conductivity approximately 2 orders of magnitude higher than the hydraulic conductivity to DI water.