• Advances in environmental research
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• v.12 no.1
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• pp.1-15
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• 2023

Wastewater of anthropogenic origin is known to harbor various bacteria that are known to be of potential risk to human health and environment. It is of utmost importance to monitor such water sources. Coliforms present in the sewage water samples of municipal sewage treatment plants located at three different places in the South Gujarat region (Surat, Navsari and Vapi) of India were analyzed for their coliforms load as well as tested for their drug resistance. Using cultivation-based techniques microbial load and drug resistance (Amoxicillin, Tetracycline, Ciprofloxacin, Erythromycin, Trimethoprim and Sulphamethoxazole) were analyzed. Water treatment statistically significantly decreased the bacterial load in Vapi and Navsari samples. The optical density of with and without antibiotics of all the three locations was shown to increase significantly after 72 hours. Of all the isolates tested, except isolate 'VA5' (resisted up to 90 ㎍ of Ampicillin) all other isolates resisted 256 ㎍ concentration of antibiotics tested. This study indicates that the sewage water is being contaminated with drugs and/or antibiotics due to industrial and/or anthropogenic activities. Regular monitoring of the water quality is required followed by implementation of environmental laws for reducing the pollutants, that are of human health and environment concern.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.4
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• pp.75-86
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• 2004

This paper proposes a method to speed up the document image binarization using a water flow model. The proposed method extracts the region of interest (ROI) around characters from a document image and restricts pouring water onto a 3-dimensional terrain surface of an image only within the ROI. The amount of water to be filed into a local valley is determined automatically depending on its depth and slope. The proposed method accumulates weighted water not only on the locally lowest position but also on its neighbors. Therefore, a valley is filed enough with only one try of pouring water onto the terrain surface of the ROI. Finally, the depth of each pond is adaptively thresholded for robust character segmentation, because the depth of a pond formed at a valley varies widely according to the gray-level difference between characters and backgrounds. In our experiments on real document images, the Proposed method has attained good binarization performance as well as remarkably reduced processing time compared with that of the existing method based on a water flow model.

• Geomechanics and Engineering
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• v.36 no.2
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• pp.145-156
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• 2024

The mechanical properties of the concrete-frozen soil interface play a significant role in the stability and service performance of construction projects in cold regions. Current research mainly focuses on the precast concrete-frozen soil interface, with limited consideration for the more realistic cast-in-place concrete-frozen soil interface. The two construction methods result in completely different contact surface morphologies and exhibit significant differences in mechanical properties. Therefore, this study selects silty clay as the research object and conducts direct shear tests on the concrete-frozen soil interface under conditions of initial water content ranging from 12% to 24%, normal stress from 50 kPa to 300 kPa, and freezing temperature of -3℃. The results indicate that (1) both interface shear stress-displacement curves can be divided into three stages: rapid growth of shear stress, softening of shear stress after peak, and residual stability; (2) the peak strength of both interfaces increases initially and then decreases with an increase in water content, while residual strength is relatively less affected by water content; (3) peak strength and residual strength are linearly positively correlated with normal stress, and the strength of ice bonding is less affected by normal stress; (4) the mechanical properties of the cast-in-place concrete-frozen soil interface are significantly better than those of the precast concrete-frozen soil interface. However, when the water content is high, the former's mechanical performance deteriorates much more than the latter, leading to severe strength loss. Therefore, in practical engineering, cast-in-place concrete construction is preferred in cases of higher negative temperatures and lower water content, while precast concrete construction is considered in cases of lower negative temperatures and higher water content. This study provides reference for the construction of frozen soil-structure interface in cold regions and basic data support for improving the stability and service performance of cold region engineering.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.540-545
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• 2006

The objective of the study is to assess the water quality improvement resulted from the rearrangement of the irrigation water supply systems at Mankyeong River and Ansung Chun basin. There is a mixed type of watershed composed of urban and rural areas in the region. The water intake facilities for agricultural use such as reservoir, weir and pumping station are generally located at upstream river where the water quality maintains relatively clean. However, this study focuses on moving the water intake to downstream and rearranging the irrigation water supply system, then investigating how effective they are for water quality improvement in the river. When the water intake is moved downstream, the stream flow is increased as much as the amount of irrigation water that is to be taken upstream. The augmented flow which is frequently referred to as environmental flow can function as dilution water for improving the quality of polluted water that is originated from the wastewater in tributaries.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.157-157
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• 2022

Recent decades have seen all over the world increasing drought in some regions and increasing flood in others. Climate change has been alarming in many regions resulting in degradation and diminution of available freshwater. The effect of global warming and overpopulation associated with increasing irrigated farming and valuable agricultural lands could be particularly disastrous for coastal areas like the one of Benin. The coastal region of Benin is under a heavy demographic pressure and was in the last decades the object of important urban developments. The present study aims to roughly study the general effect of climate change (Sea Level Rise: SLR) and groundwater pumping on Seawater intrusion (SWI) in Benin's coastal region. To reach the main goal of our study, the region aquifer system was built in numerical model using SEAWAT engine from Visual MODFLOW. The model is built and calibrated from 2016 to 2020 in SEAWAT, and using WinPEST the model parameters were optimized for a better performance. The optimized parameters are used for seawater intrusion intensity evaluation in the coastal region of Benin The simulation of the hydraulic head in the calibration period, showed groundwater head drawdown across the area with an average of 1.92m which is observed on the field by groundwater level depletion in hand dug wells mainly in the south of the study area. SWI area increased with a difference of 2.59km² between the start and end time of the modeling period. By considering SLR due to global warming, the model was stimulated to predict SWI area in 2050. IPCC scenario IS92a simulated SLR in the coastal region of Benin and the average rise is estimated at 20cm by 2050. Using the average rise, the model is run for SWI area estimation in 2050. SWI area in 2050 increased by an average of 10.34% (21.04 km²); this is expected to keep increasing as population grows and SLR.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1997.10a
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• pp.73-76
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• 1997

The purpose of this study is to find sedimentation patterns variation in Saemangeum coastal sea region. Water circulations are calculated diagnostically from the observed water temperature and salinity data and wind data and tidal residual current. Three dimensional movements of injected particles due In currents, turbulence and sinking velocity are tracked by the Euler-lagrange method. Calculated sedimentation patterns of riverine material are highly similar to the observed ones.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.77-89
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• 2004

A computer model is developed to assess optimal ground water pumping rates and optimal locations of wells in a coastal region. A sharp interface model is used to simulate the freshwater and salt water flows. Drawdown, upconing, saltwater intrusion and the contamination of well are considered in this model. A genetic algorithm with parallel processing is used to identify the optimal solution.

• Journal of the Korean Professional Engineers Association
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• v.41 no.2
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• pp.51-58
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• 2008

In this paper is described "the water resources policy, a new paradigm of water resources control. the characteristic of rainfall in Korea and the compatibility of a new water routes opening in natural river". Also the construction of the Korean grand waterway in the view of disaster prevention, flood control, irrigation and environment-friendly transportation is needed eventually. And I detail a routes of Korean grand waterway, using of a flood gate, supply of irrigation water. cruse duration, activating under developed region and economic efficiency.

• 한국해양학회지
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• v.30 no.4
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• pp.250-261
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• 1995

This study was carried out to investigate the distribution of the benthic polychaetous community in Kamak Bay, in summer of 1993. Polychaetes, the dominant faunal group comprising 74.5% of the total number of fauna, consisted of a total of 84 species with a mean density of 112 indiv.m/SUP -2/. The number of species and density were higher in the mouth area of the bay than in the rest of the bay. The most dominant Polychaete was Tharyx sp.(31.9%), followed by Lumbrineris longifolia (27.5%), Chone sp.(4.5%) and Glycera chirori (4.2%). The correspondence analysis revealed that the study area could be divided into four regions. Northeastern channel and southern mouth region of the bay, named Tharyx-Chone assemblage, sustained higher polychaetous density and species number due to the active water exchange with the outer off-sea, whereas northwestern region of the bay had the poorest polychaetous assemblage in the species number and faunal density owing to the blocking water exchange, high organic enrichment in sediment, and low dissolved oxygen content of bottom water. The central region, named Praxillella-Terebellides assemblage and Gly-cera assemblage, was the transition zone between another two region in species composition.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.2
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• pp.127-133
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• 2008

We assessed the coastal landscape of Jeju and Busan cities, respectively. In the study, we tried to estimate the coastal landscape based on the micro-scale and visualization landscape concepts. According to the estimation, the seawater pumping line causes the serious problem of coastal landscape. It means that water management treatment system of coastal region has been an important problem in Jeju city and Busan city since the slight problem was not corrected such as the distributions of pipeline of the pumping system making a bad view in coastal region. To solve the problem, we observed the pipeline distributions that were on the surface around the coastal region. we proposed two methods, that is, one is a short time treatment, the other is a long time one. The short is based on the colour treatment, which is pipeline colour changing into surround natural one. The long time is the construction design method which needs construction management method. Although the later method was very useful in Jeju island and Busan city. However, it takes a lot of time and money. Therefore, in the situation, the short time plan is more useful method than the long time one.