• Journal of Korea Water Resources Association
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• v.54 no.8
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• pp.553-566
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• 2021

River confluence is often characterized by shear layer and the associated strong mixing. In natural rivers, the main channel and its tributary can be separated by the shear layer using contrasting colors. The shear layer can be easily observed using aerial images from satellite or unmanned aerial vehicles. This study proposes a low-cost identification method extracting geographic features of the shear layer using RGB aerial image. The method consists of three stages. At first, in order to identify the shear layer, it performs image segmentation using a Gaussian mixture model and extracts the water bodies of the main channel and tributary. Next, the self-organizing map simplifies the flow line of the water bodies into the 1-dimensional curve grid. After that, the curvilinear coordinate transformation is performed using the water body pixels and the curve grid. As a result, the shear layer identification method was successfully applied to the confluence between Nakdong River and Nam River to extract geometric shear layer features (confluence angle, upstream- and downstream- channel widths, shear layer length, maximum shear layer thickness).

• Journal of Korea Water Resources Association
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• v.56 no.2
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• pp.103-113
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• 2023

The river confluence is a section in which two rivers with different topographical and hyrodynamic characteristics are combined into one, and it is a section in which rapid flow, inflow of sediments, and hydrological topographic changes occur. In the confluence section, the flow of fluid occurs due to the difference in density due to the type of material or temperature difference, which is called a density flow. It is necessary to accurately measure and observe the confluence section including a certain section of the main stream and tributaries in order to understand the mixing behavior of the water body caused by the density difference. A comprehensive analysis of this water mixture can be obtained by obtaining flow field and flow rate information, but there is a limit to understanding the mixing of water bodies with different physical properties and water quality characteristics of rivers flowing with stratigraphic flow. Therefore, this study attempts to grasp the density flow through the water temperature distribution in the confluence section. Among the extensive data of the river, vertical data and water surface data were acquired, and through this, the stratification phenomenon of the confluence was to be confirmed. It was intended to analyze the mixed pattern of the confluence by analyzing the water mixing pattern according to the water temperature difference using the vertical data obtained by measuring the repair volume by installing the ADCP on the side of the boat and measuring the real-time concentration using YSI. This study can supplement the analysis results of the existing water quality measurement in two dimensions. Based on the comparative analysis, it will be used to investigate the current status of stratified sections in the water layer and identify the mixing characteristics of the downstream section of the river.

• Journal of Korean Society for Quality Management
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• v.43 no.1
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• pp.103-124
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• 2015

Purpose: This paper proposes a structured approach based on Quality Function Deployment (QFD) for service development in the banking industry. Methods: SERVQUAL is modified and adopted as a tool to understand customer requirements for the QFD. Fuzzy theory is used to resolve the subjectivity and ambiguity of customer requirements and satisfaction. This research also uses the importance- satisfaction model to construct an additional House of Quality (HOQ). A pair of houses of quality provides a confluence of results to avoid a risk of depending solely on the results of a single HOQ. Results: A case study is introduced with three domestic banks. Conclusion: The proposed approach effectively addresses a service development problem.

• Journal of Chest Surgery
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• v.28 no.6
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• pp.619-622
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• 1995

We report a successful surgical correction of type II truncus arteriosus without using a extra-cardiac conduit in an 2 month-old infant. The truncal root is transected, and the confluence of branch pulmonary arteries is brought anterior to the aorta by using Lecompte`s maneuver. The aorta is then reconstructed directly with an end-to-end anastomosis. The right ventricular outflow tract is reconstructed by anastomosing the posterior wall of the confluence directly to the upper part of the vertical right ventriculotomy. A monocusp ventricular outflow patch is then placed anteriorly to complete reconstruction of the right ventricular outflow tract. The patient had an uncomplicated postoperative course and was discharged on the 9th postoperative day.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1991-1993
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• 2002

This paper presents the PDMS surface characteristic change after the plasma process and the electroosmotic flow control technique for the two-dimensional focusing in the micro channels made of PDMS and glass. The channels are fabricated by plastic molding and micromachining technique. To observe the surface characteristic change as time elapses, we measure the contact angle of water on the surface and the velocity of the electroosmotic flow in a channel. The electric field adequate for focusing of a core flow in a confluence channel is obtained by the experiment. The computer simulation is performed to obtain the width and the depth of the core flow for several junction angles of the confluence channel.

• The Korean Journal of Nuclear Medicine
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• v.30 no.1
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• pp.126-129
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• 1996

Spontaneous perforation of CBD in infant is a rare but fatal disease. We report a case of bile leakage from common bile duct in 11 months old girl with progressive abdominal distension and vomiting, preoperatively diagnosed by hepatobiliary scan with 99mTc-DISIDA, which was confirmed by surgery, Operative cholangiogram showed a small perforation at the confluence of cystic duct and common bile duct with mild fusiform dilatation, and no definite abnormality in confluence of the common bile duct and pancreatic duct. Simple drainage of the free peritoneal bilous fluid and T-tube drainage were performed without any evidence of the complication. Patient was inevitable for 6 months OPD follow-up examination.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.2
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• pp.41-49
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• 2000

To understand the signal fluctuation of a wide-range oxygen sensor installed at the exhaust confluence point, when a misfiring is triggered in a cylinder, the steady state and the transient response characteristics of the sensor to the flow of the misfired gas were investigated quantitatively. It was recognized that the steady state output voltage of the sensor increased higher when it contacted the misfired gas even though the fueling condition was the same as the normal combustion case and this characteristic enabled the application of the wide-range oxygen sensor for the misfire detection. The transient response was compared at different engine speeds and it was found that the response speed increased with the engine speed. The signal fluctuation was also estimated quantitatively, using these steady state and transient response of the sensor, and the estimated signal showed satisfactory correlation with the measurements.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.182-183
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• 2005

• 한국전산유체공학회:학술대회논문집
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• 2008.08a
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• pp.32.4-32.4
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• 2008

• 한국방재학회:학술대회논문집
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• 2009.02b
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• pp.74.2-74.2
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• 2009