• Korean Journal of Agricultural Science
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• 제10권2호
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• pp.324-333
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• 1983

Modeling of longterm runoff is theoritically based on waterbalance analysis. Simplified equation of water balance with rainfall, evapotranspiration and soil moisture storage could be formulated into regression model with variables of rainfall, pan evaporation and previous-month streamflow. The hydrologic response of water shed could be represented lumpedly, qualitatively and deductively by regression coefficients of water-balance regression model. Characteristics of regression modeling of water-balance were summarized as follows; 1. Regression coefficient $b_1$ represents the rate of direct runoff component of precipitation. The bigger the drainage area, the less $b_1$ value. This means that there are more losses of interception, surface detension and transmission in the downstream watershed. 2. Regression coefficient $b_2$ represents the rate of baseflow due to changes of soil moisture storage. The bigger the drainage area and the milder the watershed slope, the bigger b, value. This means that there are more storage capacity of watershed in mild downstream watershed. 3. Regression coefficient $b_3$ represents the rate of watershed evaporation. This depends on the s oil type, soil coverage and soil moisture status. The bigger the drainage area, the bigger $b_3$ value. This means that there are more watershed evaporation loss since more storage of surface and subsurface water would be in down stream watershed. 4. It was possible to explain the seasonal variation of streamflow reasonably through regress ion coefficients. 5. Percentages of beta coefficients what is a relative measure of the importance of rainfall, evaporation and soil moisture storage to month streamflow are approximately 89%, 9% and 11% respectively.

• Journal of Wetlands Research
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• 제22권3호
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• pp.194-199
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• 2020

Unlike in the past, the world is facing water shortages due to climate change and difficulties in simultaneously managing the risks of flooding. The Four Major Rivers project was carried out with the aim of realizing a powerful nation of water by managing water resources and fostering the water industry, and the construction period was relatively short compared to the unprecedented scale. Therefore, the prediction and analysis of how the river environment changes after the Four Major Rivers Project is insufficient. Currently, part of the construction section of the Four Major Rivers Project is caused by repeated erosion and sedimentation due to the effects of sandification caused by large dredging and flood-time reservoirs, and the head erosion of the tributaries occurs. In order to solve these problems, the riverbed maintenance work was installed, but it resulted in erosion of both sides of the river and the development of new approaches and techniques to keep the river bed stable, such as erosion and excessive sedimentation, is required. The water agent plays a role of securing a certain depth of water for the main stream by concentrating the flow so much in the center and preventing levee erosion by controlling the flow direction and flow velocity. In addition, Groyne products provide various ecological environments by forming a natural form of riverbeds by inducing local erosion and deposition in addition to the protection functions of the river bank and embankment. Therefore, after reviewing the method of determining the shape of the Groyne structure currently in use by utilizing the mobile limit flow rate and marginal reflux force, a new Critical Movement Velocity(${\bar{U}}_d$) and a new resistance coefficient formula considering the mathematical factors applicable to the actual domestic stream were developed and the measures applicable to Groyne installation were proposed.

• Korean Security Journal
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• 제18호
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• pp.119-141
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• 2009

Administrative execution by proxy is one of forced executions of administration and is also called as "enforced execution by proxy" in which administration institutions or the third party executes by proxy on behalf of parties who did not execute obligations under administration law and files claims to compensate expenses required in the proxy execution. Despite the actual site of administrative execution by law, social problems are generated because various violence and behaviors of infringement of human rights between executer and obligator are rampant and thus causing human damages since forced execution by physical force is carried out and cases of police indictments and petition to human rights committee are gradually increasing. Majority of people mobilized in this actual site of violence are supplied by private security companies which provide service contract and mobilization of people without qualification of guards or security service and irrational execution by proxy and violent actions by so-called service hooligans connected to violence organizations are now becoming social issues. In these actual sites of violence, structurally very complicated problems such as economic rights, right of residence, struggle for living, and intervention by outsiders are contained. This thesis has analyzed causes of outbreaks of violence and discussed about improvement countermeasure by paying attention to mobilization of people by private security companies. As the result, through revision and improvement of laws and systems, execution institution and policemen must be present at actual sites of execution by proxy to control physical execution of private security companies to be carried out legally and when violent collisions are occurring, it shall be stipulated that police should immediately intervene. Practices of execution by proxy of execution administration institutions shall be avoided and causes of occurrences of violence shall be eliminated by discrete decisions of execution by proxy, elimination of service contract conditions focused on accomplishments, and stipulation of responsibility of execution institutions when problems occur. Practices of solving petitions through collective actions of obligators shall be eliminated and strict enforcement of laws such as disturbance of official execution or compensation claims for expenses of execution by proxy must be carried out and intervention by the third parties must be intercepted. Mobilization of manpower by security companies shall be limited to people with prior registration who have acquired and finished qualification and education by security business law and before putting them on actual sites, it shall be obliged that execution plan with clear written records of working location, mission, and work rules must be submitted in advance to police station in charge and also they must be controlled to follow laws and statutes such as uniform and equipments. In addition, personal criminal responsibility for violent actions must be clearly stipulated and advanced securing soundness of security companies such as limits of service contracts with records of accidents is required. Order placement behaviors of special organizations under the pretext of rehabilitation business must be eradicated and companies with capability and strong intention of observation of laws must be able to receive orders by intercepting chains of contracts and sub-contracts. Issues of improvement countermeasure of social problem, living, and compensation including rights of residence and environment are excluded from the discussion.

• Journal of Korean Society of Environmental Engineers
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• 제36권8호
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• pp.521-527
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• 2014

The objectives of study are 1) to enhance the filed scale BMPs model of HRSM4BMP for simulation of watershed scale and 2) to evaluate the enhanced HRSM4BMP model. Thus pre-process and post-process module were developed and HRSM4BMP was linked to SWAT routing module. After enhancement of model, enhanced HRSM4BMP model was applied to Heaan watershed in Kangwon province with Vegetative filter strip (2 m) in subwatershed #14 and reduction of sediment load was evaluated by watershed scale in outlet. The results of simulation, sediment load was reduced by 4 percent during 3 years in outlet. The result of this study is expected to be used Long-term BMPs establishing plan in South Korea.

• Journal of Korea Water Resources Association
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• 제42권12호
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• pp.1079-1089
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• 2009

The objective of this study is to develop the accurate, robust and high resolution two-dimensional numerical model that solves the computationally difficult hydraulic problems, including the wave front propagation over dry bed and abrupt change in bathymetry. The developed model in this study solves the conservative form of the two-dimensional shallow water equations using an unsplit finite volume scheme and HLLC approximate Riemann solvers to compute the interface fluxes. Bed-slope term is discretized by the divergence theorem in the framework of FVM for application of unsplit scheme. Accurate and stable SGM, in conjunction with the MUSCL which is second-order-accurate both in space and time, is adopted to balance with fluxes and source terms. The exact C-property is shown to be satisfied for balancing the fluxes and the source terms. Since the spurious oscillations in second-order schemes are inherent, an efficient slope limiting technique is used to supply TVD property. The accuracy, conservation property and application of developed model are verified by comparing numerical solution with analytical solution and experimental data through the simulations of one-dimensional dam break flow without bed slope, steady transcritical flow over a hump and two-dimensional dam break flow with a constriction.

• Korean Journal of Veterinary Service
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• 제38권3호
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• pp.173-180
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• 2015

Environmental pesticides used for insect control can be transferred from plants to animals even to livestock animals through food chain. Human beings also can be exposed to pesticides by consuming polluted dairy products, including meats, eggs and other milk products. Therefore, the Ministry of Food and Drug Safety (MFDS) established Standard for Pesticide Residue Limits in dairy products. The QuEChERS (quick, easy, cheap, effective, rugged and safe) methods for detecting residual pesticides are relatively well established for fruits and vegetables, however, the methods for meat have not been appropriately studied yet. In the present work, pyraclofos was used as an organophosphate pesticide to examine its tissue residue in experimental animals by QuEChERS methods. For this, pyraclofos (150 mg/kg body weight) was orally administered to male rats once a day for 2 days. After 6, 12, and 24 hr of the treatment, the tissue residues in liver and femoral muscle of the rats were determined using QuEChERS methods followed by HPLC analyses. In preliminary studies, the recovery rates of spiking samples of pyraclofos demonstrated approximately 109~110% from the tissues. In previous study, pyraclofos tissue residues were observed with significantly high levels in livers and muscles at 6 hr of oral treatment. Then, they were almost completely disappeared after 24 hr of the administration, indicating the orally exposed pyraclofos is rapidly absorbed and distributed to body organs, then quickly excreted from the body with a negligible level of tissue residue. The alterations in blood chemistry as well as the histopathology of heart, lung, liver, spleen and kidney have also been investigated in the experimental animals for assessing acute toxic effects of pyraclofos. The obtained blood chemistry indexes (ALT and AST) showed maximum peak values at 12 hr after the oral administration and decreased to the normal levels at 24 hr of the treatment. Histopathologic observation exhibited acute hepatic damages at 24 hr of the treatment. In conclusion, we suggest that QuEChERS method can be adequately optimized for the analysis of pyraclofos residues in animal tissues.

• Journal of Korea Water Resources Association
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• 제49권6호
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• pp.459-467
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• 2016

LISFLOOD-FP model in which channel flows are resolved separately from the floodplain flows using either a kinematic or diffusive wave approximation has been used to analyze flooding behavior on the lower Mankyung River influenced by backwater. A calibration and validation process was applied using the previous flood events to assess the model performance. Sensitivity analysis was conducted for main calibrated parameters, such as Manning roughness coefficient and downstream boundary condition. Also, we examined the effect of warm-up for the initial conditions. The results show that the computed hydrograph is in good agreement with measured data on the study reach, even though it was a hydrologic kinematic wave model. The sensitive analysis show that the difference between the computed results may be greater depending on the used calibrated parameters and that the sufficient calibration/validation process against various flood events is necessary. If the flood inundation simulation is performed using the validated model, it is expected to be able to contribute about river planning and policy decision-making for flood damage reduction.

• Journal of Korea Water Resources Association
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• 제45권2호
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• pp.151-163
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• 2012

The distribution of gravel-bed materials in mountainous river is formed by the process of deposition and transportation of sediment responding to stream power of the latest flood that is over the certain scale. The particle size of bed material was surveyed in the longitudinal points of river and detail points of a specific meandering section and used to estimate the critical velocity and stream power. Yang's critical unit stream power and Bagnold's critical stream power for gravel-bed materials increased with the distance from downstream to upstream. Dimensionless shear stress based on the designed flood discharge in Shields diagram was evaluated that the gravel-bed materials in most survey points may be transported as form of bedload. The mean diameter in the meandering section was the biggest size in first water impingement point of inflow water from upstream and the second big size in second water impingement point by reflection flow. The mean diameters were relatively the small sizes in points right after water impingement. The range of mean critical velocity was 0.77~2.60 m/s and critical unit stream power was big greatly in first water impingement point. The distribution of critical stream power, range of 7~171 $W/m^2$, was shown that variation in longitudinal section was more obvious than that of cross section and estimated that critical stream power may be affected greatly in first and second water impingement point.

• Korean Journal of Environment and Ecology
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• 제22권6호
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• pp.658-665
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• 2008

One of the characteristics of fluvial river channel with sand bed-material is the existence of movable sand bars not occupied with vegetation. However, sand bars at the Hahoe's reach of the Nakdong River showing a double-meandering channel has been changed into expanding vegetation area. Moreover, sand material, in recent years, has stopped moving to downstream in channel and the number and area of bare bars which did not occupied by vegetation have been decreased. In order to find out the mechanism, we carried out the channel characteristics surveys such as hydro-geomorphologic, soil physio-chemical and vegetation surveys were conducted twice on autumn season in 2005,2006. The results so far achieved showed that the reduced discharge of transported sediment and duration of dry season might be critical factors for the spread of luxuriant vegetation. The vegetation area was significantly expanded by floods exceeding the subsequent dominant flow discharge. Furthermore, the expansion of vegetation area was highly correlated with the supply of organic matter, nutrients and alteration of soil texture by sediment deposition during the flooding event.

• Korean Journal of Clinical Laboratory Science
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• 제49권2호
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• pp.135-140
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• 2017

Polymerase chain reaction (PCR) was used to detect cattle material from processed meat products. Seventy-eight different commercial processed meat products were purchased from several big food marts. Among them, 17 products contained cattle material (10 samples contained only cattle, 5 samples mixed with cattle and porcine, 2 samples mixed with cattle, porcine and chicken). The genomic DNA was extracted directly from the processed meat products, and strain-specific primer targeting the 16S ribosomal RNA mitochondrial gene was used. All PCR products were cloned into the pGEM-T easy vector and sequenced. Consequently, the PCR products were amplified from 10 processed meat products, which contained only cattle material in our conditions. Furthermore, PCR reactions showed the same results at mixed samples. The DNA sequence obtained from pGEM-T easy/PCR products showed more than 95% identity with Bos taurus 16S rRNA gene using homology analysis. In conclusion, we suggest that the method using PCR, as performed in this study, could be useful in detecting cattle material in processed meat products. Moreover, our system could be applicable in inspection procedures to improve the verification of correct labeling for import and export processed meat products.