• Title/Summary/Keyword: Confluence

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Numerical analysis of flow and bed change at a confluence of the Namhan River and the Seom River using a two-dimensional model (2차원 수치모형을 이용한 남한강과 섬강 합류부 구간의 흐름 및 하상변동 해석)

  • Park, Moonhyung;Kim, Hyung Suk;Baek, Chang Hyun
    • Journal of Korea Water Resources Association
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    • v.51 no.12
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    • pp.1273-1284
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    • 2018
  • The flow and bed change were analyzed using the CCHE2D model, which is a two-dimensional numerical model, at a confluence of the Namhan River and Seom River where deposition occurs predominantly after the "Four Major Rivers Restoration Project." The characteristic of the junction is that the tributary of Seom River joined into the curved channel of the main reach of the Namhan River. The CCHE2D model analyzes the non-equilibrium sediment transport, and the adaptation lengths for the bed load and suspended load are important variables in the model. At the target area, the adaptation length for the bed load showed the greatest influence on the river bed change. Numerical simulation results demonstrated that the discharge ratio ($Q_r$) change affected the flow and bed change in the Namhan River and Seom river junction. When $Q_r{\leq}2.5$, the flow velocity of the main reach increased before confluence, thereby reducing the flow separation zone and decreasing the deposition inside the junction. When $Q_r$>2.5, there was a high possibility that deposition would be increased, thereby forming sand bar. Numerical simulation showed that a fixed sand bar has been formed at the junction due to the change of discharge ratio, which occurred in 2013.

The Direction of Inter-Korean Cooperation on Ecological Conservation along the Han and Imjin Rivers Confluence: Focusing on Conservation of Migratory Species (한강-임진강 합류부 환경·생태보전을 위한 남북협력 방향: 이동성 생물종 보전을 중심으로)

  • Choi, Hyun-Ah;Han, Donguk
    • Journal of Wetlands Research
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    • v.24 no.3
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    • pp.155-160
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    • 2022
  • The debate of South-North transboundary rivers must be expanded from the existing cooperation in water resources towards cooperation within ecosystem conservation. Regarding the Han and Imjin rivers confluence water system, the nature of the estuarine ecosystem must be conserved considering the aspect of climate change. Furthermore, the agenda of maintaining continuous inter-Korean communication and cooperation should focus on ecosystem conservation, including conserving migratory species that inhabit both Koreas. Notably, within the Han and Imjin rivers confluence, transboundary rivers are abundant legally protected species such as Grus vipio, Anser fabalis, Anser cygnoides, Platalea minor, Lutra lutra, Prionailurus bengalensis which suggests a strong need for a debate regarding habitat conservation. This study analyzed the ecosystem conditions and environmental aspects within the confluence of Han and Imjin rivers. In addition, this study provided step wise approach of ecosystem conservation that consider conditions for potential direct inter-Korean cooperation. The inter-Korean cooperation mentioned in this study will be developed into legitimate cooperation once the results from monitoring the ecosystem of transboundary rivers, awareness raising are exchanged.

The Flood Control of the Namgang and Andong Reservoir System by an Optimization Procedure (최적화(最適化) 기법(技法)에 의한 남강(南江)-안동(安東)댐의 홍수조절(洪水調節))

  • Kim, Sheung Kown;Yoon, Yong Nam;Lee, Sung Yoon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.8 no.1
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    • pp.49-60
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    • 1988
  • The use of an Incremental Dynamic Programming (IDP) for real-time flood control operation is investigated. The optimization model has been applied for the Namgang and Andong hypothetical flood control system in the Nakdong river basin. The objective of the operation is defined to minimize the maximum flow at the confluence of downstreams from the two reservoirs. The results are compared to the direct summation of the flood routing results from individual flood control simulation run. It shows that peak flow at the confluence is reduced markedly by reducing peak outflows from individual reservoirs and by balancing the time of the peak release between the two reservoirs.

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A Study of the Style Type and Formative Properties of Short Front and Long Back Skirts in the Early Joseon Dynasty (조선 전기 전단후장형 치마의 스타일 유형과 조형적 특성 연구)

  • Yi Ji Hwang;Sohee Kim
    • Journal of the Korean Society of Clothing and Textiles
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    • v.47 no.2
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    • pp.215-231
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    • 2023
  • This study classifies short front long back skirts from the Joseon Dynasty by style type, identifies their formative characteristics based on their external morphological properties and internal composition, and examines their correlation with Korean thought. A literature review and empirical research were conducted for this study. The style of short front long back skirts is classified as inverted "b"-shaped, lower lip, wavy, trapezoid with a raised center hem, or half-circle. As such, this skirt possesses the formative properties of imbalance, variability of shape, intentional three-dimensionality, and confluence. In other words, with an imbalance resulting from the difference in length between the front and back, these skirts are characterized by variability in shape created by intentional three-dimensionality expressed as intentional three-dimensional beauty, the confluence of planes and dimensions, as well as of materials and colors. These properties are correlated with Korean ways of viewing the world. This study contributes to the development of Korean designs.

Successful Endoscopic Treatment of Hepatic Duct Confluence Injury after Blunt Abdominal Trauma: Case Report

  • Park, Chan Ik;Park, Sung Jin;Lee, Sang Bong;Yeo, Kwang Hee;Choi, Seon Uoo;Kim, Seon Hee;Kim, Jae Hun;Baek, Dong Hoon
    • Journal of Trauma and Injury
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    • v.29 no.3
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    • pp.93-97
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    • 2016
  • Hepatic duct confluence injury, which is developed by blunt abdominal trauma, is rare. Conventionally, bile duct injury was treated by surgical intervention. In recent decades, however, there had been an increase in radiologic or endoscopic intervention to treat bile duct injury. In a hemodynamically stable patient, endoscopic intervention is considered as the first-line treatment for bile duct injury. A 40 year-old man was transferred to the emergency department of ${\bigcirc}{\bigcirc}$ trauma center after multiple blunt injuries. Contrast-enhanced abdominal computed tomography performed in another hospital showed a liver laceration with active arterial bleeding, fracture of the sacrum and left inferior pubic ramus, and intraperitoneal bladder rupture. The patient presented with hemorrhagic shock because of intra-peritoneal hemorrhage. After resuscitation, angiographic intervention was performed. After angiographic embolization of the liver laceration, emergency laparotomy was performed to repair the bladder injury. However, there was no evidence of bile duct injury on initial laparotomy. On post-trauma day (PTD) 4, the color of intra-abdominal drainage of the patient changed to a greenish hue; bile leakage was revealed on magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography (ERCP). Bile leakage was detected near the hepatic duct confluence; therefore, a biliary stent was placed into the left hepatic duct. On PTD 37, contrast leakage was still detected but both hepatic ducts were delineated on the second ERCP. Stents were placed into the right and left hepatic ducts. On PTD 71, a third ERCP revealed no contrast leakage; therefore, all stents were removed after 2 weeks (PTD 85). ERCP and biliary stenting could be effective treatment options for hemodynamically stable patients after blunt trauma.

Determination of Ecological Flow at the Confluence of Nakdong River and Gumho River Using River2D (River2D를 이용한 낙동강-금호강 합류부의 생태유량 산정)

  • Seo, Il Won;Park, Inhwan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.3
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    • pp.947-956
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    • 2013
  • In this study, WUA (Weighted Usable Area) was calculated to determine ecological flow at the confluence of Nakdong River and Gumho River by using River2D. To calibrate River2D, simulation results of River2D were compared with calibrated HEC-RAS simulation results and the optimum parameters were determined. After parameter calibration, WUA of Zacco platypus and Zacco temmincki which are dominant species in Nakdong River was calculated with changing upstream flowrate. From the result, WUA is changed according to flowrate and growth stage. In the flowrate-WUA/A graph, ecological flow can be determined as $33.3m^3/s{\sim}39.96m^3/s$ in Nakdong River and $3.6m^3/s{\sim}4.32m^3/s$ in Gumho River. After dredging for Four major rivers restoration project, WUA of Zacco platypus and Zacco temmincki were calculated by using the ecological flow. The results show that WUA after dredging are decreased when compared with undredged condition. WUA of Common carp is 2~3 times bigger than WUA of Zacco platypus and Zacco temmincki at the dredged condition in Nakdong River.

Significance of Cerebral Venography in Surgery of Petroclival Meningiomas (추체사대 수막종의 수술과 관련하여 뇌 정맥조영상의 의미)

  • Hwang, Sung-Kyun;Gwak, Ho-Shin;Paek, Sun Ha;Oh, Chang-Wan;Lee, Sang Hyung;Kim, Dong Gyu;Kim, Hyun Jib;Jung, Hee-Won
    • Journal of Korean Neurosurgical Society
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    • v.30 no.10
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    • pp.1200-1209
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    • 2001
  • Objective : A thorough understanding of the related venous structure is mandatory for successful removal of the petroclival meningiomas. This study was planned to investigate the guideline for safe ligation and incision of transverse or sigmoid sinuses and the importance of drainage pattern of vein of $Labb{\acute{e}}$ in surgical removal of petroclival meningiomas. Patients and Methods : The authors reviewed the venogram of the consecutive 37 cases of petroclival meningiomas and retrospectively analyzed their surgical findings. The drainage pattern of confluence of Herophili was classified as Type A(confluent & equal on both sides), Type B(confluent & non-dominant on tumor side), Type C(confluent & dominant on tumor side) and Type D(unilateral drainage only) as these findings gave the information on safe ligation and resection of the sinus. Usefulness of intraoperative test clamping of sinus for safe ligation was also reviewed. The vein of $Labb{\acute{e}}$ was analyzed with respect to its draining point and its collaterals to other superficial veins. Results : Contraindications of the sinus ligation and resection according to the drainage pattern at the confluence of Herophili were Type C(n=10, 27%)and Type D(n=4, 11%). Patients with Type A(n=12, 32%)and Type B(n=11, 30%) were tolerable to sinus ligation ipsilateral to tumor, if the test clamping proved to be safe. Identification of no brain swelling, after intraoperative test clamping of the sinus for more than 30 minutes performed in 7 out of 11 cases, was a reliable indicator of safe sinus ligation. The drainage pattern of the vein of $Labb{\acute{e}}$, especially low-lying type, could predict the possibility of postoperative hemorrhage and infarction. Its drainage into tentorium or superior petrosal sinus, however, made the transtentorial approach impossible, leading to restricted operative field. Conclusion : For a successful removal of the petroclival meningiomas preoperative venogram should be examined carefully. The extent of exposure in a planned approach can be estimated by analyzing the variation of sinuses and the drainage pattern of vein of $Labb{\acute{e}}$.

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Hydrological Properties Depending on River Bed Elevation Gap at Confluence (하천 합류부에서 지류단락에 따른 수리학적 특성)

  • Kim, Hyun-Kyum;Han, Jin-Young;Kim, Chul-Moon;An, Won-Sik
    • Proceedings of the Korea Water Resources Association Conference
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    • 2011.05a
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    • pp.174-178
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    • 2011
  • 본 연구에서는 자연하도 합류부의 수리학적 특성을 파악하기 위하여 $45^{\circ}$ 합류각을 가진 실험수로에서 수리모형실험을 실시하고, 2차원 SMS모형의 RMA2 모듈을 이용한 수치해석을 실시하였다. 연구를 위하여 최근 대두되고 있는 본류를 준설함에 따라 발생하는 본류와 지류의 하상고 차이에 따른 합류부의 흐름특성을 검토 하였다.

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Two Examples of 'Confluence' in Periodic Slow Wave Structure (주기적인 구조내의 마이크로파의 공류현상)

  • McDiarmid, Don R.;Walker, George B.
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.6 no.1
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    • pp.54-56
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    • 1969
  • 무손실 주기구조에 의한 단대역의 제거와 영, π모드에 대한 공류현상에 대하여 기술하였다. 특수한 2개의 구조내의 2개의 통과모드가 공류점에서 영이 아닌 군속도를 가질 수 있음이 해석에 의하여 알려졌으며 이 공류현상은 모드분리를 뚜렷이 하기 때문에 선형가속기로서 유용하다.

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