• Proceedings of the Korea Water Resources Association Conference
• /
• 2005.05b
• /
• pp.1199-1203
• /
• 2005

Combined sewer overflows(CSOs) are themselves a significant source of water pollution. Therefore, the control of urban drainage for CSOs reduction and receiving water quality protection is needed. Examples in combined sewer systems include downstream storage facilities that detain runoff during periods of high flow and allow the detained water to be conveyed by an interceptor sewer to a centralized treatment plant during periods of low flow. The design of such facilities as stormwater detention storage is highly dependant on the temporal variability of storage capacity available(which is influenced by the duration of interevent dry periods) as well as the infiltration capacity of soil and recovery of depression storage. As a result, a contiunous approach is required to adequately size such facilities. This study for the continuous long-term analysis of urban dranage system used analytical Probabilistic model based on derived probability distribution theory. As an alternative to the modeling of urban drainage system for planning or screening level analysis of runoff control alternatives, this model have evolved that offer much ease and flexibility in terms of computation while considering long-term meteorology. This study presented rainfall and runoff characteristics or the subject area using analytical Probabilistic model. Runoff characteristics manifasted the unique characteristics of the subject area with the infiltration capacity of soil and recovery of depression storage and was examined appropriately by sensitivity analysis. This study presented the average annual COSs and number of COSs when the interceptor capacity is in the range 3xDWF(dry weather flow). Also, calculated the average annual mass of pollutant lost in CSOs using Event Mean Concentration. Finally, this study presented a dicision of storage volume for CSOs reduction and water quality protection.

• Journal of Korean Neurosurgical Society
• /
• v.58 no.1
• /
• pp.1-8
• /
• 2015

Treatment of Leptomeningeal carcinomatosis (LMC) from solid cancers has not advanced noticeably since the introduction of intra-cerebrospinal fluid (CSF) chemotherapy in the 1970's. The marginal survival benefit and difficulty of intrathecal chemotherapy injection has hindered its wide spread use. Even after the introduction of intraventricular chemotherapy with Ommaya reservoir, frequent development of CSF flow disturbance, manifested as increased intracranial pressure (ICP), made injected drug to be distributed unevenly and thus, the therapy became ineffective. Systemic chemotherapy for LMC has been limited as effective CSF concentration can hardly be achieved except high dose methotrexate (MTX) intravenous administration. However, the introduction of small molecular weight target inhibitors for primary cancer treatment has changed the old concept of 'blood-brain barrier' as the ultimate barrier to systemically administered drugs. Conventional oral administration achieves an effective concentration at the nanomolar level. Furthermore, many studies report that a combined treatment of target inhibitor and intra-CSF chemotherapy significantly prolongs patient survival. Ventriculolumbar perfusion (VLP) chemotherapy has sought to increase drug delivery to the subarachnoid CSF space even in patients with disturbed CSF flow. Recently authors performed phase 1 and 2 clinical trial of VLP chemotherapy with MTX, and 3/4th of patients with increased ICP got controlled ICP and the survival was prolonged. Further trials are required with newly available drugs for CSF chemotherapy. Additionally, new LMC biologic/pharmacodynamic markers for early diagnosis and monitoring of the treatment response are to be identified with the help of advanced molecular biology techniques.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.6 no.4
• /
• pp.67-82
• /
• 2003

A 2-dimensional hydrodynamic model has been applied to understand water circulation pattern in Lake Deacheong. The simulation results have been used in sediment transport modeling. A sediment transport model using a particle tracking method has been developed to simulate sediment transport in the ocean, river and reservoir. The model was applied to estimate transport track of particulate pollutants in the lake. The hydrodynamic model was verified for water level variations and showed good agreements. Through the results we found out that water velocity is less than 5 cnysec for mean yearly flow and more than 120 cnysec at some points for the simulated flood flow. The incoming sediment particles in flood season reached into the Daecheong Dam. But the incoming sediment particles in the mean flow were settled down at riverbed and didn't move into the dam. These results can be used in setting up water quality management plan in the lake.

• The Journal of the Korea Contents Association
• /
• v.10 no.8
• /
• pp.426-432
• /
• 2010

A level-set finite-element method is employed to investigate the free surface flow of two conceptual fish passage designs. While one design has a right-angled entrance from the reservoir to the fish passage chute, the other has a curved-shaped entrance. The numerical results are validated with hydraulic experiments through comparison of the free surface location and the pressure distribution in the spillway. It is observed that the right-angled design yields a curved free surface and pressure distribution in the vicinity of the entrance due to large strains, whereas the curved-shaped design yields a smooth flow transition with small strains. The subatmospheirc pressure distributions near the spillway ogee crest for both designs exhibit similar flow patterns. It is concluded that the curved-shaped design is more favorable for fish passage because of the feature of a smooth flow transition with small strains.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.43 no.2
• /
• pp.59-68
• /
• 2001

A water balance analysis was performed for a paddy field neighboring the Dongchang stream, downstream of the Unmun reservoir, which is constructed for the urban water supply. Daily rainfall data were collected and irrigation water flow rate, drainage flow rate, evaportranspiration, infiltration, and piezometeric head were measured in the field. The flow rates were continuously observed by water level logger during the growing season. The evaportranspiration and the infiltration were measured by N-type depletion meter and cylindrical infiltrometer, respectively. PVC pipes with 12mm diameter were used for piezometric head measurement. Total Irrigation and drainage flows were 3,608mm and 1,170mm in 1999, and 3,971mm and 1,548mm in 2000, respectively. The mean and range of the daily infiltration rate were 4.4mm/d and 3.4mm/d to 5.5mm/d in 1999 and 5.1mm/d and 4.1mm/d to 6.5mm/d in 2000, respectively. The net ground water flow including the change of soil water storage was 2,855mm in 1999 and 2,540mm in 2000. The evapotranspiration was 458.3mm in 1999 and 553.5mm in 2000. The range of daily evapotranspiration rate was from 1.6 to 8.7mm/d. The return flow ratio was about 32% in 1999 and 39% in 2000 and three year average was 35% including previous study in 1997. The amount of irrigation water was much higher than design standards or references in this study, This was caused by the inadequate water management practice in the area where water was oversupplied on farmers’ request rather than following sound water management principles.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.18 no.4
• /
• pp.101-115
• /
• 1991

A study on the method of evaluation the urban amenity structure in Pusan city was established. Finally a survey sites out of 41 regions were selected on the basis of questionnaires : Taejong-dae and Haeun-dae as a seascape, Pumosa and Daesin-park as a mountain, Daechong-park and Seongjigok-park as a mixed, and Chungryulsa, Yongdoosan-park and U. N. Cemetry as a urban type. The abstracted results of amenity elements were revealed as natural environments including convex type as beach, reservoir, valley and mountain, and plant elements including woods and flower beds which raised amenity. The elements of social surroundings including children's playing, the aged's rest, and elements of structures including historic and memorial structures and high buildings. Amenity element made up of each space by region were abstracted from the Semantic Differential method. According to the factor analysis on the ground SD scale values, Kaiser's measure of sampling adequacy for 24 variables is 08602 and very high. Four factors including pleasantness, healthiness, convenience and safety showed 54.42 percent for total variance. By means of multiple regression, the model was as follows : Y=1.6636+0.3684X4+0.1955X11+0.1614X15-0.1688X23+0.1468X24. Therefore, Y:amenity, X4:beautiful-ugly, X11:clean-dirty, X15:creative-imitative, X23:cozy-dreary, X24:free-restrained. All variables in the model were significant at 0.001 level. According to the results of regression on satisfaction, the variables of satisfaction affecting amenity are the size of green space, the condition of management and the harmony with the surroundings. I think the considerating on the above could improve amenity of each region and further Pusan city.

• Tunnel and Underground Space
• /
• v.28 no.4
• /
• pp.304-324
• /
• 2018

Singapore government is strongly promoting the development and utilization of underground space in national level due to the nature of the city state which lacks the land. As well as conventional underground utilization in shallow depth such as metro and underground roads, large rock cavern utilization has been started after the successful completion of the underground ammunition depot in the rock, and Jurong Rock Cavern, the second large underground cavern project has just been completed. In this paper, after evaluating the conditions of the underground development in rock mass through the analysis of the geology of Singapore, the history and current status of underground development are examined. Several creative development plans from Singapore government such as underground reservoirs, underground automation logistics systems and underground warehouses storage etc. are introduced with technical issues. This paper also discusses the problems and issues related to the development of large underground space in rock mass in Singapore. It is expected that such active development of underground space in Singapore can give many opportunities and also challenges for rock engineering and industry in the future.

• Journal of Korean Society of Water and Wastewater
• /
• v.27 no.4
• /
• pp.413-428
• /
• 2013

In this study, Ant Colony Algorithm(ACO) was used for optimal model. ACO which are metaheuristic algorithm for combinatorial optimization problem are inspired by the fact that ants are able to find the shortest route between their nest and food source. For applying the model to water distribution systems, pipes, tanks(reservoirs), pump construction and pump operation cost were considered as object function and pressure at each node and reservoir level were considered as constraints. Modified model from Ostfeld and Tubaltzev(2008) was verified by applying 2-Looped, Hanoi and Ostfeld's networks. And sensitivity analysis about ant number, number of ants in a best group and pheromone decrease rate was accomplished. After the verification, it was applied to real water network from S water treatment plant. As a result of the analysis, in the Two-looped network, the best design cost was found to $419,000 and in the Hanoi network, the best design cost was calculated to $6,164,384, and in the Ostfeld's network, the best design cost was found to $3,525,096. These are almost equal or better result compared with previous researches. Last, the cost of optimal design for real network, was found for 66 billion dollar that is 8.8 % lower than before. In addition, optimal diameter for aged pipes was found in this study and the 5 of 8 aged pipes were changed the diameter. Through this result, pipe construction cost reduction was found to 11 percent lower than before. And to conclusion, The least cost design model on water distribution system was developed and verified successfully in this study and it will be very useful not only optimal pipe change plan but optimization plan for whole water distribution system.

• Journal of Environmental Health Sciences
• /
• v.29 no.2
• /
• pp.38-44
• /
• 2003

This study was performed to investigate the levels of fluoride (F), calcium (Ca), and magnesium (Mg) in water samples taken from five reservoirs or direct sources on a stream used for agricultural or domestic water in the Iksan and Wanjoo areas, Jeon-buk, Korea, and to find a possible link between Ca or Mg and fluoride in water sources in theses areas. The samples were collected by the recommendation methods of the World Health Organization and analyzed by the recommendations of the Japanese Standard Methods. Statistical analyses were performed by the analysis of variance and correlation analysis. The F levels in water samples wire 0.80~2.53 ppm. In four sampling sites the water fluoride levels exceeded 1 ppm. which if the recommended level for fluorosis/caries control. The Ca levels in water samples were 6.82~12.98 ppm, and the Mg levels were 0.30~1.97 ppm, which are lower compared with the natural levels of water sources previously reported by other investigators. This study showed a positive correlation between Ca and Mg (r= 0.8779. p<0.01) and a negative correlation between F and Ca (r=-0.6974, p<0.05) and also between F and Mg (r=-0.5581) in the water samples. However, the study did not find remarkable relationships in fluoride levels between sampling sites. These results support the fact that there were epidemics of dental fluorosis in this area. The lack of significant positive correlations in fluoride levels between sampling sites suggests that there may be some pathways for the transfer of the metal to the water through other environmental media besides the water course. Long-term epidemiological studies are needed on the relationship between high F together with low Ca and Mg levels in the water, and total human health in this community. There should alto be a long-term monitoring of the water quality in this area.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.13 no.4
• /
• pp.177-188
• /
• 1993

Model parameters of the WASP4 applied to Lake Paldang were estimated. The methodology is based on grouping water quality constituents and relevant parameters and successively estimating each group of parameters by a trial-and-error procedure. Chlorophyll a, nitrogen cycles, phosphorus cycles, BOD and DO were simulated at the complexity level 4. A water budget analysis using the monthly records of reservoir inflows and outflows in 1989 and 1990 was made to determine seasonally-averaged flowrates at model boundaries. Estimated flowrates were used, together with the seasonal average of water quality measurements in 1989 and 1990 for the calibration and verification, respectively, of the model. Grouping water quality constituents and associated parameters proved to be efficient in estimating a number of model parameters. From the results of model calibration and verification, it was found that quantitative evaluations of nonpoint and benthic sources of organic matters are essential. Benthic sources near the entrance of the Kyeongancheon were the most significant.