• Journal of the Korean Institute of Gas
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• v.8 no.4 s.25
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• pp.15-22
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• 2004

This study has been carried out to improve the conditions of process operation through the adjustment to the flow rate and outlet pressure of LNG HP pump, one of the main process facilities, in LNG receiving terminal. We have determined optimum flow rate and applied it to the field operation by analyzing the field operating performance for all the HP pumps and the load of natural gas supply in seasonal using the ASPEN PLUS. As a results, we have get the electric cost saving for the HP pump operation and derived contribution to safety operation by reduced the LNG Process pressure.

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.426-437
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• 2004

To understand the phytoplankton community in adjacent waters of Ulchin nuclear power plant (UNPP), abundance and the size fractionated $chl-\alpha$ concentrations were evaluated through seasonal interval sampling from April 2003 to February 2004. A total of 211 different phytoplankton species was observed and mean abundance of phytoplankton in each study period ranged from 244,286 to 1,221,779 cells $L^{-1}$. The contributions of microplankton $(>20\mu{m})$ to total phytoplankton abundance ranged from 42.5 to 83.6% (average 66.1%) and those of nanoplankton $(>20\mu{m})$ ranged from 16.4 to 57.5% (average 33.9%). Total chl-$\alpha$ concentrations of phytoplankton ranged from 0.52 to $2.26\mu{g}\;L^{-1}$. The contribution of chl-$\alpha$ concentrations of microplankton was higher than that of nano- and picoplankton through the study period with exception of July 2008. The results of abundances and $chl-\alpha$ concentrations suggest that microplankton has an important role in adjacent waters of UNPP. The diminution of abundances and $chl-\alpha$ concentrations of phytoplankton was observed after passage through the cooling water system, but it was gradually recovered by mixing with the ambient waters. Our results suggested that the influence of thermal discharges on phytoplankton should be restricted within narrow limits around outlet area of thermal effluents.

• Journal of Soil and Groundwater Environment
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• v.17 no.5
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• pp.31-39
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• 2012

Chemical and isotopic variations of snowmelt provide important clues for understanding snowmelt processes and the timing and contribution of snowmelt to catchment or watershed in spring. The newly developed model includes a hydraulic exchange between mobile and immobile water (${\omega}$), and isotopic exchanges between both mobile water and ice ($f_1$) and immobile water and ice ($f_2$). Since the new model is based on the mobile-immobile water conceptualization, which is widely used for describing chemical tracer transport in snow, it allows simultaneous calculations of chemical as well as isotopic variations in snowpack discharge. We compare the model results with a study of solute transport and isotopic evolution of snowmelt in snow, using artificial rain-on-snow experiments with conservative anion ($Br^-$). These observations are used to test the newly developed model and to better understand physical processes in a seasonal snowpack where our model simulates the chemical and isotopic variations.

• Atmosphere
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• v.32 no.4
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• pp.263-276
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• 2022

The observation error of satellite radiation data that assimilated into the Korean Integrated Model (KIM) was diagnosed by applying the Hollingsworth and Lönnberg and Desrozier techniques commonly used. The magnitude and correlation of the observation error, and the degree of contribution for the satellite radiance data were calculated. The observation errors of the similar device, such as Advanced Technology Microwave Sounder (ATMS) and Advanced Microwave Sounding Unit-A shows different characteristics. The model resolution accounts for only 1% of the observation error, and seasonal variation is not significant factor, either. The observation error used in the KIM is amplified by 3-8 times compared to the diagnosed value or standard deviation of first-guess departures. The new inflation value was calculated based on the correlation between channels and the ratio of background error and observation error. As a result of performing the model sensitivity evaluation by applying the newly inflated observation error of ATMS, the error of temperature and water vapor analysis field were decreased. And temperature and water vapor forecast field have been significantly improved, so the accuracy of precipitation prediction has also been increased by 1.7% on average in Asia especially.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.7
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• pp.181-193
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• 2021

Thailand's tourism industry contributed to over three trillion baht in 2019. Tourist attractions across Thailand attract tourists around the world with their natural scenery, lifestyles, and cultures, especially in those called "second-tier cities". Community enterprises play a vital role to drive the tourism industry to local areas. However, most community enterprises lack professional accounting knowledge. This research aims to provide guidelines for ecotourism cost management of community enterprises in Thailand. Participatory Action Research (PAR) was employed to investigate the current circumstances of the Banlaem enterprise by using in-depth interviews to identify problems in cost management. Then, the focus and small group meetings were organized to monitor and evaluate solutions. The results reveal that the cost of VIP-Two Days trip was generating the highest net profit and margin, followed by VIP-One Day trip, but net losses were detected on the Students-One Day trip, even though income was greater than the variable costs, revenues didn't cover fixed costs. Thus, accounting knowledge could be a major concern of these enterprises. They should systematically record revenues and expenses, set appropriate labor costs, reduce production costs by using seasonal seafood and make use of vegetables in their gardens, and price products according to their production costs.

• Korean Journal of Environment and Ecology
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• v.26 no.5
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• pp.780-786
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• 2012

A trenching method was used to determine the contribution of root respiration to soil respiration in Quercus acutissima forest in the vicinity of Gongju, Chungnam Province, Korea. $CO_2$ efflux in soil respiration plot($R_{control}$, $R_c$) and microblal respiration plot($R_{trenched}$, $R_t$) in Q. acutissima forest were measured from June 2011 to May 2012 by using IRGA soil respiration analyzer. Seasonal $CO_2$ efflux in $R_c$ and $R_t$ were higher in summer season than in winter season. In August, maximun $CO_2$ efflux in $R_c$ and $R_t$ was 1.345 and 0.897 g $CO_2\;m^{-2}\;hr^{-1}$, respectively. $CO_2$ efflux in $R_t$ was lower by 33.31% than that in $R_c$(P<0.05). In January, $CO_2$ efflux in $R_c$ and $R_t$ was 0.097 and 0.032g $CO_2\;m^{-2}\;hr^{-1}$, respectively. $CO_2$ efflux in $R_t$ was lower by 67.01% than that in $R_c$(P<0.01). The amount of annual $CO_2$ efflux from $R_c$ and $R_t$ was 4.320, 2.834kg $CO_2\;m^{-2}\;yr^{-1}$, respectively. There was a significant correlations between soil temperatures and soil respiration. Contribution of root respiration to total soil respiration in this Q. acutissima forest was 34.40%.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.21 no.1
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• pp.24-35
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• 2016

To assess the relationship between environmental factors and seasonal phytoplankton community structure, we investigated abiotic and biotic factors in Ulsan Bay, Korea. We divided the bay into two areas based on geographical characteristics and compared the difference in each factor between inner and outer bay with t-test statistics. As a result, temperature in the outer bay was higher than that of the inner bay during winter (t = -5.833, p < 0.01) and autumn (p > 0.05). However, opposite trend was observed during spring (t = 4.247, p < 0.01) and summer (t = 2.876, p < 0.05). Salinity was significantly lower in the inner bay than in the outer bay in winter, spring, and summer (p < 0.01). However, the salinity was not significantly different between the inner and the outer bay in the autumn (p > 0.05). In particular, high nutrient concentration was observed in most stations during winter season due to vertical well mixing. The nutrient concentration was significantly higher in surface layers of inner bay after rainfall, particularly in the summer. The relative contribution (approximately 70%) of < $20{\mu}m$ (nano and pico) size phytoplankton was increased in all seasons with continuously low nutrients from the offshore water due to their adaption to low nutrient without other large competitors. Interestingly, high population of Eutreptiella gymnastica was kept in the inner bay during the spring and summer associated with high DIN (nitrate+nitrite, ammonium) after river discharge following rainfall, suggesting that DIN supply might have triggered the increase of Eutreptiella gymnastica population. In addition, high density of freshwater species Oscillatoria sp. and Microcystis sp. were found in several stations of the inner bay that were provided with large amounts of freshwater from the Tae-wha River. Diatom and cryptophyta species were found to be dominant species in the autumn and winter. Of these, centric diatom Chaetoceros genus was occupied in the outer bay in the autumn. Cryptophyta species known as opportunistic micro-algae were found to have high biomass without competitors in the inner bay. Our results demonstrated that Ulsan Bay was strongly affected by freshwater from Tae-wha River during the rainy season and by the surface warm water current from the offshore of the bay during dry season. These two external factors might play important roles in regulating the seasonal phytoplankton community structures.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.1
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• pp.28-40
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• 2015

To investigate the seasonal variations of carbonaceous aerosol in Daejeon, OC (organic carbon), EC (elemental carbon) and WSOC (water soluble organic carbon) in $PM_{2.5}$ samples collected from March 2012 to February 2013 were analyzed. $PM_{2.5}$ concentrations were estimated by the sum of organic matter ($1.6{\times}OC$), EC, water-soluble ions ($Na^+$, $NH_4{^{+}}$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, $SO_4{^{2-}}$, $NO_3{^{-}}$). The estimated $PM_{2.5}$ concentrations were relatively higher in winter ($29.50{\pm}12.04{\mu}g/m^3$) than those in summer ($13.72{\pm}6.92{\mu}g/m^3$). Carbonaceous aerosol ($1.6{\times}OC+EC$) was a significant portion (34~47%) of $PM_{2.5}$ in all season. The seasonally averaged OC and WSOC concentrations were relatively higher in winter ($6.57{\times}3.48{\mu}gC/m^3$ and $4.07{\pm}2.53{\mu}gC/m^3$ respectively), than those in summer ($3.07{\pm}0.8{\mu}gC/m^3$, $1.77{\pm}0.68{\mu}gC/m^3$, respectively). OC was correlated well with WSOC in all season, indicating that they have similar emission sources or formation processes. In summer, both OC and WSOC were weakly correlated with EC and also poorly correlated with a well-known biomass burning tracer, levoglucosan, while WSOC is highly correlated with SOC (secondary organic carbon) and $O_3$. The results suggest that carbonaceous aerosol in summer was highly influenced by secondary formation rather than primary emissions. In contrast, both OC and WSOC in winter were strongly correlated with EC and levoglucosan, indicating that carbonaceous aerosol in winter was closely related to primary source such as biomass burning. The contribution of biomass burning to $PM_{2.5}$ OC and EC, which was estimated using the levoglucosan to OC and EC ratios of potential biomass burning sources, was about $70{\pm}15%$ and $31{\pm}10%$, respectively, in winter. Results from this study clearly show that $PM_{2.5}$ OC has seasonally different chemical characteristics and origins.

• Ocean and Polar Research
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• v.27 no.2
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• pp.149-159
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• 2005

Samples were collected from five stations in February, May, July, and September 2004 to investigate seasonal variations in the phytoplankton community and the relationship between dominant genera and environmental factors in Asan Bay. In February, microphytoplankton contributed 80% to the total chlorophyll a. Diatom dominated the phytoplankton community, accounting for 85.9% of the total cell number, followed by dinoflagellates (6%). Dominant species were Skeletonema costatum and Thalassiosira spp. Abundant diatom, including S. costatum and Thalassiosira spp., may be affected by water temperature and silicate at Station 1 and 2 in February 2004. In May, the nanophytoplankton contribution to total phytoplankton was higher than in other seasons. However, abundance of S. costatum and Thalassiosira spp. decreased, since the growth of S. costatum and Thalassiosira spp. might be limited by phosphates (P) resulting from low P concentration and a high DIN:DIP ratio in the outer region. In July, dominant phytoplankton groups were diatom (39%), cryptophyceae (28%), and cyanophyceae (20%). Dominant genera were Oscillatoria spp. and phytoflagellate of a monad type in the inner region (Station 1 and 2), whereas S. costatum was dominant in the outer region (Station 4 and 5). In September, dominant phytoplankton were diatom (69%) and cryptophyceae (28%). Dominant genera were phytoflagellate of the monad type, S. costatum in the inner region, while Chaetoceros spp. was dominant in the outer region.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.6
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• pp.437-449
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• 1991

Time series of barometrically adjusted sea level at Pusan, Izuhara and Hakada are analyzed to study the fluctuations of the Tsushima Current through the Korea Strait. Variability of sea levels and their differences is divided into two parts with respect to the frequency of 0.01 or 0.02 cycles per day(cpd) At lower frequency, both of sea levels and sea level difference(SLD) are coherent and in phase to each other. Pusan has smaller seasonal variations in sea level than other two stations because the effects of geostrophic current and prevailing wind have a negative influence on the seasonal thermosteric contribution to sea level change. Low frequency variability of SLD thus of the Tsushima Current is much greater in the western channel. For higher frequency parts, SLD in the eastern channel has larger variability and is not coherent with that of the western channel. Sea levels at Pusan and Izuhara are $180^{\circ}$ out of phase with SLD in the western and eastern channel respectively, whereas the Hakada level is in phase. This result indicates that eastern channel has a normal response to the along-channel winds and cross-channel geostrophy because Izuhara faces the eastern channel.