• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.113-116
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• 2003

Confluence buffers and single flux quantum (SFQ) switches are essential components in constructing a high speed superconductive Arithmetic Logic Unit (ALU). In this work, we developed a SFQ confluence buffer and an SFQ switch. It is very important to optimize the circuit parameters of a confluence buffer and an SFQ switch to implement them into an ALU. The confluence buffer that we are currently using has a small bias margin of $\pm$11％. By optimizing it with a Josephson circuit simulator, we improved the design of confluence buffer. Our simulation study showed that we improved bias global margin of 10％ more than the existent confluence buffer. In simulations, the minimal bias margin was $\pm$33％. We also designed, fabricated, and tested an SFQ switch operating in a DC mode. The mask layout used to fabricate the SFQ switch was obtained after circuit optimization. The test results of our SFQ switch showed that it operated correctly and had a reasonably wide margin of $\pm$15％.

• Restorative Dentistry and Endodontics
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• v.46 no.1
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• pp.12.1-12.9
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• 2021

Objectives: The present study aims to compare the obturation quality of 2 confluence confirmation techniques in artificial maxillary first premolars showing Vertucci type II root canal configuration. Materials and Methods: Thirty artificial maxillary premolars having Vertucci type II root canal configuration were made. They were divided into 3 groups according to the confluence confirmation technique as follows. Gutta-percha indentation (GPI) group (confluence confirmation using a gutta-percha cone and a K file); electronic apex locator (EAL) group (confluence confirmation using K files and EAL); and no confluence detection (NCD) group. In the GPI group and the EAL group, shaping and obturation were performed with the modified working length (WL). In the NCD group, shaping was performed without WL adjustment and obturation was carried out with an adjusted master cone. Micro-computed tomography was used before preparation and after obturation to calculate the percentage of gutta-percha occupied volume (%GPv) and the volume increase in the apical 4 mm. Data were analyzed using 1-way analysis of variance and post hoc Tukey's test. Results: Statistically significant difference was not found in terms of the %GPv from the apex to apical 4 mm. However, the NCD group showed a statistically significant volume increase compared with the EAL group (p < 0.05). Conclusions: In terms of gutta-percha occupied volume, no significant difference was observed among the 3 groups. Confluence confirmation using an EAL in teeth with Vertucci type II configuration showed less volume increase during canal shaping compared with no confluence confirmation.

• Progress in Superconductivity and Cryogenics
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• v.6 no.4
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• pp.41-45
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• 2004

Rapid Single flux quantum (RSFQ) confluence buffer is widely used in complex superconductive digital circuits. In this work, we have improved the currently used confluence buffer and obtained a more soundly designed confluence buffer. In simulations, improvements in the bias margins of 11 % and the global margins of 10%, compared to the previously used confluence buffer, were achieved. Global margins are very important in estimating a process error range allowed in fabrications. We used two circuit simulation tools, WRspice and Julia, to design and optimize the confluence buffer. We used Xic to obtain a mask layout. We fabricated the improved circuits by using Nb technology. The test results at low frequency showed that the improved confluence buffer operated correctly and had a very wide main bias margin of +/-43% enhanced from +/-26% of the previously used confluence buffer.

• Journal of Korea Water Resources Association
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• v.48 no.8
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• pp.625-634
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• 2015

The diverse patterns of separation zone according to the marked bed discordance by dredging at confluence in addition to the confluence angle of tributary and discharge ratio between tributary and main channels have been analyzed by CCHE2D model simulation. The separation zone is defined by inside of zero velocity boundary at down-stream of confluence. The separation zone dose not formed at the $30^{\circ}$ of confluence angle of tributary. The size of separation zone increases as the discharge ratio and confluence angle increase in general. The separation zone decreases as the dredging depth increases which shows the relative momentum reduction compared by the flow volume increasing by dredging at confluence. The contraction factor with the variation of confluence angle and discharge ratio has been investigated and confirmed the corresponding conveyance decreasing results in backwater effect. The regression equation of shape factor with confluence angle and discharge and dredging depth ratios has been suggested.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.206-215
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• 2020

This study analyzes the relationship between K-CESA of undergraduate students, and their coaching skill and creativity confluence competences. Totally, 344 students attending private colleges in G province were evaluated for their competence. The data collected were analyzed by descriptive statistics, Pearson's correlation analysis, multiple regression analysis and Sobel test, using the SPSS/PC 22.0 computer program. Our results indicate that K-CESA, coaching skill, and creative convergence fulfill the assumption of normality. Moreover, significant positive relationships were determined between K-CESA and creativity confluence, as well as between coaching skill and creativity confluence. Furthermore, K-CESA was an important factor that predicts the creativity confluence competency, and coaching skill had mediating effects on the relationship between K-CESA and creativity confluence competency. In conclusion, our results indicate that K-CESA and coaching skills are important factors that will help strengthen creativity confluence competences.

• Journal of The Korean Society of Integrative Medicine
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• v.8 no.3
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• pp.113-120
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• 2020

Purpose : The purpose of this study is to investigate creative confluence competency of occupational therapy students and to understand the correlations between five sub-elements of creative confluence competency. Methods : The subjects of this study were 132 occupational therapy students. The data collection period was from February 12, 2020, to February 28, 2020. A Google questionnaire was used to collect data through SNS; 16 data with insufficient responses were excluded, and 116 data were finally analyzed. The collected data was processed using SPSS 21.0. The data were analyzed using descriptive statistics, t-test, ANOVA, Scheffe's test and Pearson's correlation coefficient. Results : The mean scores for creative confluence competency of the occupational therapy students is as follows: Creative ability 3.12±.58, creative personality 3.29±.55, creative leadership 3.50±.53, convergent thinking 3.23±.57, confluent value creation 3.04±.59. Occupational therapy students' creative leadership competence was highest, and confluent value creation competence was lowest. The average score of creative confluence competency of occupational therapy students was 3.12±.58, and the Cronbach' α value of the creative confluence competency was .97, which was very reliable. There was a positive correlation between the five sub-elements of creative confluence competency. Conclusion : The data in this study are related to efforts to improve occupational therapy students' creative confluence competency and prepare for convergence education. And It is expected to be used as basic data for the development of occupational therapist competency to prepare for the 4th industrial revolution.

• Journal of Korea Water Resources Association
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• v.48 no.11
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• pp.879-889
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• 2015

The pattern of headward erosion at tributary and the separation zone formation in a loosed bed at confluence according to the confluence angle, discharge ratio, and dredging depth ratio have been analyzed. The separation zone is defined the inside of zero velocity boundary at downstream of confluence. The limit of separation zone occurrence is presented with dredging depth ratio. The propagation length of knickpoint increases as the confluence angle, discharge ratio, and dredging depth ratio increase in general and its regression equation has been suggested. The length and width ratios of separation zone in a loosed bed increase as discharge ratio and confluence angle increase as well as in a fixed bed. The length ratio decreases and the width ratio increases as dredging depth ratio increases results in great increase of shape factor and backwater rise by the conveyance reduction at confluence. The regression equation of shape factor with confluence angle, discharge ratio, and dredging depth ratio has been suggested.

• Journal of Korea Water Resources Association
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• v.46 no.7
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• pp.767-781
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• 2013

In this study, the hydraulic model experiments and numerical simulations are carried out to analyze the flood flow characteristics in and around a channel confluence connected asymmetrically with four channels. The numerical model applied in this study is ANSYS CFX (ver. 14) which is the commercial three-dimensional CFD model. As results of comparison between the measured and simulated water depth distributions in and around a channel confluence, the agreement is relatively well satisfied. It can be shown in this study that the water surface profiles in and around a channel confluence are significant different with the two channel directions in which the water are entering and increased inflow.

• Economic and Environmental Geology
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• v.56 no.4
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• pp.435-445
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• 2023

A delta is a depositional landform that is formed when sediment transported by a river is deposited in a relatively low-energy environment, such as a lake, sea, or a main channel. Among these, a delta formed at the confluence of rivers has a great importance in river management and research because it has a significant impact on the hydraulic and sedimentological characteristics of the river. Recently, the equilibrium state of the confluence area has been disrupted by large-scale dredging and construction of levees in the Nakdong River. However, due to the natural recovery of the river, the confluence area is returning to its pre-dredging natural state through ongoing sedimentation. The time-series data show that the confluence delta has been steadily growing since the dredging, but once it reaches a certain size, it repeats growth and retreat, and the overall size does not change significantly. In this study, we developed a model to explain the sedimentation-erosion processes in the confluence area based on the assumption that the confluence delta reaches a dynamic equilibrium. The model is based on two fundamental principles: sedimentation due to supply from the tributary and erosion due to the main channel. The erosion coefficient that represents the Nakdong River confluence areas, was obtained using data from the tributaries of the Nakdong River. Sensitivity analyses were conducted using the developed model to understand how the confluence delta responds to changes in the sediment and water discharges of the tributary and the main channel, respectively. We then used annual average discharge of the Nakdong River's tributaries to predict the dynamic equilibrium positions of the confluence deltas. Finally, we conducted a simulation experiment on the development of the Gamcheon-Nakdong River delta using recorded daily discharge. The results showed that even though it is a simple model, it accurately predicted the dynamic equilibrium positions of the confluence deltas in the Nakdong River, including the areas where the delta had not formed, and those where the delta had already formed and predicted the trend of the response of the Gamcheon-Nakdong River delta. However, the actual retreat in the Gamcheon-Nakdong River delta was not captured fully due to errors and limitations in the simplification process. The insights through this study provide basic information on the sediment supply of the Nakdong River through the confluence areas, which can be implemented as a basic model for river maintenance and management.

• Journal of Wetlands Research
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• v.16 no.1
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• pp.139-151
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• 2014

In this study, virtual confluence of $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, $75^{\circ}$ type flowing into main channel was designed to comprehend occlusion phenomenon of the mouth of river, then performed numerical analysis using the RMA-2 and SED2D model of SMS according to application of 40m, 60m, 80m, 100m Training levee corresponding to main channel width ratio. Results of simulations analysis are summarized as follows. Applying appropriate Training levee length determined by numerical analysis results, Training levee dimension for occlusion reduction was studied through the analysis of velocity, water level, bed variation at the Gamchen confluence and Wichen confluence.