• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.882-895
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• 1997

Changes in the benthic communities have been studied to investigate the environmental effects before and after the construction of Shihwa Dike in the West coast of Korea. It is suggested that sequential changes in macrofaunal assemblages progressed in two sucressional directions. In the Shihwa lake under the influence of organic enrichment. First, the appearance of 'azoic tone' or 'grossly polluted zone' developed in the area of less than 6 m in depth resulted from the severe dissolved oxygen depletion due to the eutrophication from the increased organic loading. Second, the 'polluted zone' characterized by the proliferation of the opportunistic species in organically enriched area, was found in the vicinity of the industrial discharges and nearby fluvial inputs. This benthic community succession in the Shihwa lake seemed to be caused by the various ecological events such as an eutrophication in this organically enriched environment after construction of the dike and other physico-chemical parameters like salinity and dissolved oxygen in the bottom water, which may be influenced by the irregular surface water discharge and dilution by outer seawater inflow through the water gate of the dike. On the other hand, the benthic communities in the outside of the dike showed that the species richness was more than doubled and the abundance increased almost seven times more than that before the dike construction. This may be a typical characteristics of the initial phase in benthic eutrophication, suggesting that an increased organic input area may have been reponsible for this faunal change in the study area.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.1
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• pp.58-66
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• 2014

Water pollution problems of urban rivers due to the urbanization and industrialization have been the subject of public attention. In particular, considering the fact that the characteristics of water cycle of each basin change dramatically through the development of new towns, a large number of concerns about future water quality have been raised. However, reasonable measures to predict future water quality quantitatively have not been presented by this moment. In this study, by the linkage of annual unit load generation based on long-term monitoring results of the ministry of environment (MOE) to a semi-distributed rainfall runoff model, SWMM (Storm Water Management Model), we proposed a new methodology to estimate future water quality macroscopically and testified it to verify its applicability for the estimation of future water quality of a small watershed at G new town. As a result of the estimation using Y-EMC (Yearly based Event Mean Concentration), future water quality were simulated as BOD 18.7, T-N 16.1 and T-P 0.85 mg/L respectively which could not achieve the grade III of domestic river life guidance and these criteria could be satisfied by the reduction of domestic wastewater discharge load by over 80%. The results of this study are shown to be utilized for one of basic tools to estimate and manage water quality of urban rivers in the course of new town developments.

• Economic and Environmental Geology
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• v.37 no.5
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• pp.499-508
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• 2004

Changwon City first constructed riverbank filtration plants in Book-Myeon and Daesan-Myeon in Korea in the year 2001. This study evaluated hydrogeological characteristics and groundwater flow simulation between the Nakdong River and the fluvial aquifers adjacent to the river in Book-Myeon, Changwon City. The groundwater simulation calculated the influx rate from the Nakdong River and the fluvial aquifers to pumping wells through the riverbank filtration system. The groundwater flow model utilized drilling, grain size analysis, pumping test, groundwater level measurements, river water discharge and rainfall data. Hydraulic heads calculated by the steady-state model closely matched measured heads in pumping and observation wells. According to the transient flow model, using a total pumping amount of 14,000 $m^3$/day, the flux into the pumping wells from the Nakdong River accounts for 8,390 $m^3$/day (60%), 590 $m^3$/day (4%) is from the aquifer in the rectilinea. direction to the Nakdong River, and 5,020 $m^3$/day (36%) is from the aquifer in the parallel direction to the Nakdong River. The particle tracking analysis shows that a particle from the Nakdong River moves toward the pumping wells at a rate of about 1.85 m/day and a particle from the aquifer moves toward the pumping wells at a rate of about 0.75 m/day. This study contributes to surface water/groundwater management modeling, and helps in understanding, how seasonal change affects pumping rates, water quality, and natural recharge.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.165-171
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• 2018

Atmospheric-pressure plasma (APP) was applied to determine quality characteristics of brown rice (BR) and white rice (WR) of Samkwang and Palbangmi. APP (250 W, 15 kHz, ambient air) was generated and dielectric barrier discharge was applied for 0, 10, and 20 min for 2 weeks at 4 and $25^{\circ}C$. The growth of total aerobic bacteria and mold increased depending on the storage. Water content of BR and WR decreased by storage temperature and periods. No viable counts were detected for molds by APP-treated 20 min at $4^{\circ}C$. Changes in protein and damaged starch contents in plasma were not observed. Amylose contents were not changed, but WR (Palbangmi) showed a tendency to increase. The results show that APP improved the microbial quality of BR and WR of Samkwang and Palbangmi, although further studies should be conducted to determine change in quality by APP.

• Journal of Trauma and Injury
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• v.23 no.2
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• pp.119-127
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• 2010

Purpose: This study was conducted to shorten the time spent at each stage of treatment and to reduce the total amount of time patients spend in the emergency department (ED) by applying Six Sigma in the treatment of major trauma patients. Methods: This is a comparative study encompassing 60 patients presenting to the ED of Bundang CHA Hospital from January 2008 to December 2008 and from July 2009 to March 2010. The stages of treatment for major trauma patients were divided into six categories (T1: total emergency department staying time, T2: duration of visit-radiologic evaluation time, T3: duration of visit-consult to department of admission, T4: duration of consultation-issue of hospital admissions time, T5: duration of visit-issue of hospital admissions time, T6: duration of issue of hospital admission-emergency department discharge time) and the total time patients spent in the ED was compared and analyzed for periods; before and after the application of Six Sigma. Results: After the application of Six Sigma, the numerical values in four of the six categories were significantly reduced; T2, T3, T4, and T5. However, the average of the total time patients spent in the ED did not show any remarkable change because the T6 increased highly. The level of Six Sigma increased $0.17{\sigma}$. Conclusion: The application of Six Sigma for major trauma patients in the ED resulted in a significant improvement in the error rate for the total time patients spent in the ED. The Six Sigma activity has shown great potential. Therefore, the project is expected to bring better results in every stage of treatment if the levels of the hospital facilities are improved.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.3
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• pp.115-125
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• 2001

To examine the movement of the freshwater discharged artificially into the estuary during ebbing period in the Keum River dike we observed surface salinity variations in three stations along the estuary channel in May 1998 and July 1997 and surface temperature and salinity along the ferry-route between Kunsan and Changhang during eighteen days in July 1999. Based upon the typical features of observed salinity variation, we analyzed the excursion and decay processes of the discharged water. When freshwater is discharged, the low-salinity water forms strong salinity front over the entire estuary width, which basically moves forth and back by tidal modulation along the channel, producing the sudden change of surface salinity with the front passage. Salinity distribution along the channel, which is deduced from time variation of mean salinity over the estuary width, after one tidal period from gate operation suggests that diluted low-salinity water is trapped to the front and surface salinity increases gradually toward the upstream region. This frontal distribution of salinity is interpreted to be produced by the sudden gate operation supplying and stopping of freshwater within about two hours. Daily repeat of freshwater discharge produces separation (double front) or merge between decaying and new-generated fronts depending on dike-gate opening time, and the front decays with salinity increasing if the freshwater supply is stopped more than two days. In addition, the observed fluctuations and deviations in surface salinity variation is explained in terms of the differences of fronts intensity, their transition time and temporal salinity front running along the channel, which can be generated due to artificial gate-operation for the discharging time and water volume in the estuary dike.

• Journal of Korea Water Resources Association
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• v.31 no.1
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• pp.3-12
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• 1998

Rainfall intensity under storms affects peak discharge or its time of occurrence in watershed runoff. Thus, it is reasonable to reflect the effect on the parameters of rainfall-runoff models or the governing equations of the models. This paper relates the change of the runoff coefficient of the first tank in tank model to rainfall intensity under storms. The standard four tanks have made the basic structure of the flood event model. and its modifications are as follows: it has two equal runoff coefficients in the first tank: the runoffs from first and second tanks produce delayed response through a simple delaying parameter. Applying the event simulation model to flood data from Naerinchon. runoff coefficients were estimated and their relation to rainfall intensity was analyzed. The results showed the Weak relation of the two factors. The trend of the two was fitted with the equation a1=kI$. where a1is the runoff coefficient of the first tank: I is rainfall intensity; k and m are fitting coefficients. In the verification. the model used moving averages for the calculation of I(t). If the value I(t) gave more greater value of a1(t) than that of previous time(t-1). the flood simulation was performed again from the beginning with the updated greater value of a1. The reflection of rainfall intensity on the runoff coefficient showed far better results than that of a fixed parameter.

• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.353-367
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• 2015

The goal of this study is to analyze the feedback structure of habitat changes of the Whooper Swan in Eulsukdo using system thinking to suggest a management plan for ecosystem health. Using the causal loop diagrams of population changes between Whooper Swan and other bird species in Eulsukdo, we found that the environmental changes in the roosting and foraging area affect the Whooper Swan's population. The causal loop diagrams of the Whooper Swan's roosting area indicated that the environmental changes (e.g., water level, noise, bird watching, and other experience activities) may influence their population density variation. In addition, the casual loop diagrams of the Whooper Swan's foraging area showed that the Whooper Swan's population was affected by various variables that included area factors such as surface area of freshwater, frozen water, salinity, and density of Scirpus planiculmis. Furthermore, through the integrated causal loop diagram, cumulative discharge of Nakdong estuary weir and building activities were identified as the variables that affect the population of the Whooper Swan. Thus, we selected this area as the strategic point to establish a management plan for the Whooper Swan's habitat. The results of this study will help in decision making of a long-term management plan for sustaining the environmental health of the ecosystem in Eulsukdo.

• Journal of the Korean Dietetic Association
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• v.16 no.2
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• pp.178-187
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• 2010

This study examined the effects of postoperative medical nutrition therapy on patients who had undergone bariatric surgery. Eighty seven patients who underwent bariatic-surgery at Yeouido St. Mary's Hospital from January 2007 to April 2009 were evaluated. The bariatric surgery patients included 42 Laparoscopic Roux-en Y gastric bypass (LRYGB) and 45 Laparoscopic adjustable gastric banding (LAGB) patients. Weight loss was more significant after LRYGB than after LAGB after 9 months (p<0.05). The LRYGB group was more satisfied with the weight loss (LRYGB 4.4/5.0, LAGB 3.0/5.0 p<0.001). The mean albumin, hemoglobin and hematocrit levels were significantly lower in the LRYGB group than in the LAGB group at the time of discharge (p<0.05~0.001). The GOT/GPT was significantly higher in the LRYGB group at the time of the operation than the LAGB group (p<0.01). The LRYGB group showed significantly lower intakes of total energy, carbohydrates, protein and fat from 1 week after surgery than the LAGB group. Multiple regression showed that the weight change after LRYGB was significantly more associated with the intakes of total energy at 1 week after surgery (p<0.01), SWS (sweets and high-calorie beverages) at 1 and 6 months after surgery (p<0.001), and fat at 3 months after surgery (p<0.01). In addition, LAGB was significantly more associated with the intakes of protein and NLS (non-liquid sweets) at 1 week after surgery (p<0.001, p<0.01), carbohydrate at 1 months after surgery (p<0.01), total energy at 3 months after surgery (p<0.001), HCL (high-calorie liquids) at 6 months after surgery (p<0.05), and fat at 9 months after surgery (p<0.01). These results suggest that continuous-follow-up medical nutrition therapy is needed according to the types of bariatric surgery, particularly during the weight loss phase (the first 1 week to 12 months).

• Journal of Korean Society of Environmental Engineers
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• v.34 no.6
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• pp.430-437
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• 2012

In order to obtain information on the design parameters of the horizontal laterals in floodplain filtration, laboratory-scale sand-box experiments were performed where the head distributions on the laterals and the groundwater profiles were measured according to the change in parameters including lateral diameter, hydraulic conductivity of the sand, water level at the well and raw-water supply rate. Measured data were analyzed using a numerical code in order to identify the discharge intensity distribution along the laterals. It was observed from the result that the lowering of the water level at the well had minimal adverse effect on the performance of the floodplain filtration. Results also elucidated that the low conveyance of the laterals to transmit the filtrate was compensated and supplemented by a natural augmentation in horizontal conveyance through the aquifer when the raw-water supply rate exceeded the adequate recovery rate. With this mechanism, the water quality is expected to improve further since the travel distance through the aquifer is amplified. Based on these findings it can be suggested that the diameter of the lateral used in the floodplain filtration may be smaller than those in riverbank/bed filtration. It was also found that the ratio between the head loss occurring in a lateral and the total head loss in the floodplain filtration was proportional to the exit velocities of the laterals, which may be used to design and/or evaluate the lateral in floodplain filtration.