• Proceedings of the Korean Society of Environment and Ecology Conference
• /
• 2003.10a
• /
• pp.105-126
• /
• 2003

In Korea most of annual rainfall is concentrated in several episodic heavy rains during the season of summer monsoon and typhoon. Because of uneven rainfall distribution many dams have been constructed in order to secure water supply in dry seasons. The Han River system has the most dams among Korean rivers, and the river is a series of dams now. Reservoirs need different strategy of water quality control from river water. Autochthonous organic matter and phosphorus should be the major target to be controlled in lakes. In this Paper some problems are discussed that makes efforts of water quality improvement ineffective in lakes of Korea, even after the substantial investment to wastewater treatment facilities.1) Phosphorus is the key factor controlling eutrophication of lakes and the reduction ofphosphors should be the major target of water treatment. However, water quality management strategy in Korea is still stream-oriented, and focused on BOD removal from sewage. Phosphorus removal efficiency remains as low as 10-30%, because biological treatment is adopted for both secondary treatment and advanced treatment. The standard for TP concentration of the sewage treatment plant effluent is 6 mgP/l in most of regions, and 2 mg/l in enforced region near metropolitan water intake point. TP in the effluents of sewage treatment plants are usually 1-2 mg/1, and most of plants meet the effluent regulation without a further phosphorus removal process. The generous TP standard for effluents discourages further efforts to improve phosphorus removal efficiency of sewage treatment. Considering that TP standard for the effluent is below 0.1 mg/l in some countries, it should be amended to below 0.1 mg/l in Korea, especially in the watershed of large lakes.2) Urban runoff and combined sewer overflow are not treated, even though their total loading into lakes can be comparable to municipal sewage discharges on dry days. Chemical coagulation and rapid settling might be the solution to urban runoff in regard of intermittent operation on only rainy days.3) Aggregated precipitation in Korea that is concentrated on several episodic heavyrains per year causes a large amount of nonpoint source pollution loading into lakes. It makes the treatment of nonpoint source discharge by methods of other countries of even rain pattern, such as retention pond or artificial wetland, impractical in Korea.4) The application rate of fertilizers in Korea is ten times as high as the average ofOECD countries. The total manure discharge from animal farming is thought to be over the capacity of soil treatment in Korea. Even though large portion of manure is composted for organic fertilizer, a lot of nutrients and organic matter emanates from organic compost. The reduction of application rate and discharge rate of phosphorus from agricultural fields should be encouraged by incentives and regulations.5) There is a lot of vegetable fields with high slopes in the upstream region of the HanRiver. Soil erosion is severe due to high slopes, and fertilizer is discharged in the form of adsorbed phosphorus on clay surface. The reduction of soil erosion in the upland area should be the major preventive policy for eutrophication. Uplands of high slope must be recovered to forest, and eroded gullies should be reformed into grass-buffered natural streams which are wider and resistant to bank erosion.

• Geomechanics and Engineering
• /
• v.37 no.6
• /
• pp.599-614
• /
• 2024

To evaluate the safety status of deteriorated segments in a submarine shield tunnel during its service life, a seepage model was established based on a cross-sea shield tunnel project. This model was used to study the migration patterns of erosive ions within the shield segments. Based on these laws, the degree of deterioration of the segments was determined. Using the derived analytical solution, the internal forces within the segments were calculated. Lastly, by applying the formula for calculating safety factors, the variation trends in the safety factors of segments with different degrees of deterioration were obtained. The findings demonstrate that corrosive seawater presents the evolution characteristics of continuous seepage from the outside to the inside of the tunnel. The nearby seepage field shows locally concentrated characteristics when there is leakage at the joint, which causes the seepage field's depth and scope to significantly increase. The chlorine ion content decreases gradually with the increase of the distance from the outer surface of the tunnel. The penetration of erosion ions in the segment is facilitated by the presence of water pressure. The ion content of the entire ring segment lining structure is related in the following order: vault < haunch < springing. The difference in the segment's rate of increase in chlorine ion content decreases as service time increases. Based on the analytical solution calculation, the segment's safety factor drops more when the joint leaks than when its intact, and the change rate between the two states exhibits a general downward trend. The safety factor shows a similar change rule at different water depths and continuously decreases at the same segment position as the water depth increases. The three phases of "sudden drop-rise-stability" are represented by a "spoon-shaped" change rule on the safety factor's change curve. The issue of the poor applicability of indicators in earlier studies is resolved by the analytical solution, which only requires determining the loss degree of the segment lining's effective bearing thickness to calculate the safety factor of any cross-section of the shield tunnel. The analytical solution's computation results, however, have some safety margins and are cautious. The process of establishing the evaluation model indicates that the secondary lining made of molded concrete can also have its safety status assessed using the analytical solution. It is very important for the safe operation of the tunnel and the safety of people's property and has a wide range of applications.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.19 no.10
• /
• pp.1861-1871
• /
• 1994

This paper presents efficient real time software implementation methods for the grayscale morphological composite function processing (FP) system. The proposed method is based on a matrix representation of the composite FP system using a basis matrix composed of structuring elements. We propose a procedure to derive the basis matrix for composite FP systems with any grayscale structuring element (GSE). It is shown that composite FP operations including morphological opening and closing are more efficiently accomplished by a local matrix operation with the basis matrix rather than cascade operations, eliminating delays and requiring less memory storage. In the second part of this paper, a VLSI implementation architecture for grayscale morphological operators is presented. The proposed implementation architecture employs a bit-serial approach which allows grayscale morphological operations to be decomposed into bit-level binary operation unit for the p-bit grayscale singnal. It is shown that this realization is simple and modular structure and thus is suitable for VLSI implementation.

• Journal of Environmental Impact Assessment
• /
• v.4 no.1
• /
• pp.25-35
• /
• 1995

The objective of the study is to produce preferential impact assessment factors for Environmental Impact Assessment by considering regional features and public participation in the initial stages of EIA. In order to produce preferential impact assessment factors, the study was carried out through theoretical research and a survey of public awareness as a ways to reflect public participation based on theoretical research. The survey of public awareness was conducted in the form of an interview to review the impact which the construction of atomic power plants at Hyo-am village, Jang-an, Kyungsang Province and Bi-hak village, Suhsang-myon, Ulsan-Kun will have on the surrounding environment: to reflect public participation on deciding preferential assessment: and to determine the extent of alternatives of the proposed project. As the result of the study, the following were identified as preferential assessment factors in the settlement and surrounding areas cultivation marine products, change of temperature of seawater due to flow of warm water, land use(negative), noise vibration during construction, existing plants, erosion accumulation, influx of manpower for construction(negative), recreation landscaping during construction and operation, change in flow of transportation during construction, the quality of seawater during construction and operation were produced as preferential assessment factors in both settlement area and neighboring areas. In the settlement area, the educational environment(negative & positive) and positive aspects of the influx of manpower for construction were also identified as preferential assessment factors.

• Journal of Environmental Impact Assessment
• /
• v.4 no.3
• /
• pp.15-26
• /
• 1995

The objective of the study is to produce preferential impact assessment factors for Environmental Impact Assessment by considering regional features and public participation in the initial stages of EIA. In order to produce preferential impact assessment factor, the study was carried out through theoretical research and a survey of public awareness as way to reflect public participation based on theoretical research. The survey of public awareness was conducted in the form of an interview to review the impact which the construction of atomic power plants at Hyo-am village, Jang-an, Kyungsang Province and Bi-hak village, Suhsang-myon, Ulsan-Kun will have on the surrounding environment : to reflect public participation on deciding preferential assessment: and to determine the extent of alternatives of the proposed project. As the result of the study, the followings were identified as preferential assessment factors in the displacing settlement and surrounding areas: cultivation marine products, change of temperature of seawater due to flow of warm water, land use (negative), noise vibration during construction, existing vegetations, erosion sedimentation, influx of manpower for construction(negative), recreation landscaping during construction and operation, change in flow of transportation during construction, the quality of seawater during construction and operation were produced as preferential assessment factors in both displacing area and neighboring areas. In the displacing settlement area, the educational environment(negative & positive) and positive aspects of the influx of manpower for construction were also identified as preferential assessment factors.

• Tribology and Lubricants
• /
• v.28 no.6
• /
• pp.315-320
• /
• 2012

For proper functioning, general machines usually need lubricant oil as a cooling, cleaning, and sealing agent at points of mechanical contact. The quality of lubricant oil can deteriorate during operation owing to various causes such as high temperature, combustion products and extraneous impurities. In this study, a heavy load stopped during operation, and the oil was analyzed to check whether any impurities were added. Extraction using acetonitrile followed by reaction with BSTFA(bistrimethylsilyl trifluoroacetamide) showed that, trimethylsilylated ethylene glycol was present in the lubricant oil. To quantify the ethylene glycol in the oil, deuterium-substituted ethylene glycol, which acted as an internal standard, was added to the sample and then extracted with the solvent. Next, the extract was reacted with the derivatizing agent(BSTFA) and then analyzed with GC/MS. The detection limit of this method was found to be $0.5{\mu}g/g$ and the recovery of oil containing $20,000{\mu}g/g$ of ethylene glycol was measured to be 94.8%. A damaged O-ring and eroded cylinder liner were found during the overhaul, which implied the leakage of coolant containing ethylene glycol into the lubricating system. The erosion of the cylinder liner was assumed to be due to cavitation of the coolant in the cooling system.

• Journal of the Korean Society of Radiology
• /
• v.13 no.3
• /
• pp.489-493
• /
• 2019

Obesity is increasing in our country due to lack of lifestyle and physical activity. Semi-automatic program is used in existing fat calculation program using computed tomography. Although methods for solving related problems have been proposed, this study proposes an algorithm using morphology operation and We want to solve the problem with a new method that has a simple procedure and a relatively small amount of computation. As a result of repetition of erosion and expansion Automatic fat mass calculation can be done in the future by using the developed partitioning result. By providing an accurate segmentation tool, it will be helpful to doctors and reduce the expense and inspection cost of retesting. through morphology operation, it was found that the problem was solved from the image.Automatic fat mass calculation can be done in the future by using the developed partitioning result. By providing an accurate segmentation tool, it will be helpful to doctors and reduce the expense and inspection cost of retesting.

• Journal of Convergence for Information Technology
• /
• v.11 no.2
• /
• pp.41-46
• /
• 2021

The method of the edge detection algorithm based on grayscale mathematical morphology has the advantage that image noise can be removed and processed in parallel, and the operation speed is fast. However, the method of detecting the edge of an image using a single structural scale element may be affected by image information. The characteristics of grayscale morphology may be limited to the edge information result of the operation result by repeatedly performing expansion, erosion, opening, and containment operations by repeating structural elements. In this paper, we propose an edge detection algorithm that applies a structural element with strong directionality to noise and then applies weighted entropy to each pixel information in the element. The result of applying the multi-scale structural element applied to the image and the result of applying the directional weighted entropy were compared and analyzed, and the simulation result showed that the proposed algorithm is superior in edge detection.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.9
• /
• pp.1865-1870
• /
• 2011

In this paper, we propose an effective method that automatically detects flaws in air deck by using non-destructive testing. First, Gamma correlation transform, 7 ${\times}$ 7 and 13 ${\times}$ 13 Sobel mask apply to the image of air deck acquired non-destructive testing in order to detect the edge of the image. Second, the edge detection area is smoothed and corrected by mean binarization method. Finally, the region of flaws in air deck is detected by a labeling method after removing the noise by the erosion and the dilation operation. In experimental results, we showed that the proposed detection method is effective in air deck.

• Journal of information and communication convergence engineering
• /
• v.12 no.3
• /
• pp.168-172
• /
• 2014

In this paper, we propose an algorithm that can efficiently detect and monitor multiple ships in real-time. The proposed algorithm uses morphological operations and edge information for detecting and tracking ships. We used smoothing filter with a $3{\times}3$ Gaussian window and luminance component instead of RGB components in the captured image. Additionally, we applied Sobel operator for edge detection and a threshold for binary images. Finally, object labeling with connectivity and morphological operation with open and erosion were used for ship detection. Compared with conventional methods, the proposed method is meant to be used mainly in coastal surveillance systems and monitoring systems of harbors. A system based on this method was tested for both stationary and non-stationary backgrounds, and the results of the detection and tracking rates were more than 97% on average. Thousands of image frames and 20 different video sequences in both online and offline modes were tested, and an overall detection rate of 97.6% was achieved.