• Journal of Korean Society of Coastal and Ocean Engineers
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• v.14 no.2
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• pp.136-150
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• 2002

To improve the water quality of the recently constructed Siwhaho, sluice gates were operated to allow free exchange of water with the sea. This estuarine lake connected to the outer sea through narrow gates is affected mainly by flushing by gate operation and river flows and wind forcing sometimes. As a predicting tool far the water qualities, a three-dimensional finite volume model CE-QUAL-ICM is incorporated into a finite element hydrodynamic model, TIDE3D. In coupling these two different modules, a new error minimization technique is applied by considering conservation of mass. Model tests for one year after calibration and validation using field observation show that eutrophication and other biological changes reach quasi-steady state after initial 60 days of simulation, thus it would be necessary to consider moderate ramp up option to remove initial uncertainties due to cold start option. Sediment-water interaction might not be a concern in the long-term simulation, since its effect is negligible. Simulated results show the newly applied scheme can be applied with satisfaction not only fur lessening of eutrophic processes in an estuarine lake but also looking for some active circulation to improve water quality.

• Journal of Wetlands Research
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• v.21 no.spc
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• pp.61-68
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• 2019

Recently, climate indices represented by quantifying atmospheric-ocean circulation patterns have been widely used to predict hydrologic variables for considering long-term climate variability. Hydrologic forecasting models based on artificial neural networks have been developed to provide accurate and stable forecasting performance. Forecasts of hydrologic variables considering climate variability can be effectively used for long-term management of water resources and environmental preservation. Therefore, identifying significant indicators for hydrologic variables and applying forecasting models still remains as a challenge. In this study, we selected representative climate indices that have significant relationships with dam inflow time series in the Han-River basin, South Korea for applying the dam inflow forecasting model. For this purpose, the ensemble empirical mode decomposition(EEMD) method was used to identify a significance between dam inflow and climate indices and an artificial neural network(ANN) ensemble model was applied to overcome the limitation of a single ANN model. As a result, the forecasting performances showed that the mean correlation coefficient of the five dams in the training period is 0.88, and the test period is 0.68. It can be expected to come out various applications using the relationship between hydrologic variables and climate variability in South Korea.

• Journal of the Korea Institute of Building Construction
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• v.18 no.5
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• pp.447-453
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• 2018

Since 1960, Korea the town center was developed intensively due to rapid industrial development. As a result of the development, the population was concentrated in urban areas and the green area was decreased. Due to the decrease of the green area, the circulation system of the rainwater was changed, hence the rainwater was not introduced into the groundwater., On the other hand, the water on the surface of the road was changed into the water for flowing to the river and evaporation. The changes in the water flow cause many problems, and the depletion of the groundwater does not create an environment in which microorganisms and plants can live. in Korea, permeable pavement construction is increased to solve these problems, but existing pavement blocks have many problems. The pores of the permeable block are clogged due to the accumulation of dust or whitening phenomenon, and the permeability is lost. In this study, the solution of the problems of existing permeable block were suggested by using polymer and artificial permeable pipe, and strength, permeability and service life are increased, The relationship between the substitution rate of the polymer and the mixing ratio of the artificial permeable pipe was analyzed.

• Korean Circulation Journal
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• v.54 no.1
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• pp.30-39
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• 2024

Background and Objectives: Intravascular ultrasound (IVUS) evaluation of coronary artery morphology is based on the lumen and vessel segmentation. This study aimed to develop an automatic segmentation algorithm and validate the performances for measuring quantitative IVUS parameters. Methods: A total of 1,063 patients were randomly assigned, with a ratio of 4:1 to the training and test sets. The independent data set of 111 IVUS pullbacks was obtained to assess the vessel-level performance. The lumen and external elastic membrane (EEM) boundaries were labeled manually in every IVUS frame with a 0.2-mm interval. The Efficient-UNet was utilized for the automatic segmentation of IVUS images. Results: At the frame-level, Efficient-UNet showed a high dice similarity coefficient (DSC, 0.93±0.05) and Jaccard index (JI, 0.87±0.08) for lumen segmentation, and demonstrated a high DSC (0.97±0.03) and JI (0.94±0.04) for EEM segmentation. At the vessel-level, there were close correlations between model-derived vs. experts-measured IVUS parameters; minimal lumen image area (r=0.92), EEM area (r=0.88), lumen volume (r=0.99) and plaque volume (r=0.95). The agreement between model-derived vs. expert-measured minimal lumen area was similarly excellent compared to the experts' agreement. The model-based lumen and EEM segmentation for a 20-mm lesion segment required 13.2 seconds, whereas manual segmentation with a 0.2-mm interval by an expert took 187.5 minutes on average. Conclusions: The deep learning models can accurately and quickly delineate vascular geometry. The artificial intelligence-based methodology may support clinicians' decision-making by real-time application in the catheterization laboratory.

• Journal of Chest Surgery
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• v.38 no.2 s.247
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• pp.101-109
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• 2005

Background: In sudden cardiac arrest, the effective maintenance of coronary artery blood flow is of paramount importance for myocardial preservation as well as cardiac recovery and patient survival. The purpose of this study was to directly compare the effects of pulsatile and non-pulsatile circulation to coronary artery flow and myocardial preservation in cardiac arrest condition. Material and Method: A cardiopulmonary bypass circuit was constructed in a ventricular fibrillation model using fourteen Yorkshire swine weighing $25\~35$ kg each. The animals were randomly assigned to group I (n=7, non-pulsatile centrifugal pump) or group II (n=7, pulsatile T-PLS pump). Extra-corporeal circulation was maintained for two hours at a pump flow of 2 L/min. The left anterior descending coronary artery flow was measured with an ultrasonic coronary artery flow measurement system at baseline (before bypass) and at every 20 minutes after bypass. Serologic parameters were collected simultaneously at baseline, 1 hour, and 2 hours after bypass in the coronary sinus venous blood. The Mann-Whitney U test of STATISTICA 6.0 was used to determine intergroup significances using a p value of < 0.05. Result: The resistance index of the coronary artery was lower in group II and the difference was significant at 40 min, 80 min, 100 min and 120 min (p < 0.05). The mean velocity of the coronary artery was higher in group II throughout the study, and the difference was significant from 20 min after starting the pump (p < 0.05). The coronary artery blood flow was higher in group II throughout the study, and the difference was significant from 40 min to 120 min (p < 0.05) except at 80 min. Serologic parameters showed no differences between the groups at 1 hour and 2 hours after bypass in the coronary sinus blood. Conclusion: In cardiac arrest condition, pulsatile extracorporeal circulation provides more blood flow, higher flow velocity and less resistance to coronary artery than non-pulsatile circulation.

• Korean Institute of Interior Design Journal
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• v.23 no.2
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• pp.3-11
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• 2014

Light has been considered as one of the most important elements in architectural design. Light provides occupants in buildings a lot of architectural experiences by interrelating the space, shape and other design elements. Especially, natural light is the valuable source to create the better indoor space compared to artificial light. It is a sustainable energy source and offers a more natural environment. It also enables occupants to perceive the form and depth of space. In general. many of architects including Henri Ciriani have tried to design buildings with natural light expecting optimum indoor environment. Therefore, this paper tried to examine the works of Henri Ciriani and analyze how to control the light in his works. For this purpose, two museums designed by Henri Ciriani-Arles Museum of Archaeology and Great War Historical Museum in Peronne - were selected to analyze how Henri Ciriani used light in his design phase and applied it to his museum works. According to the results of the study, it has been proved that Henri Ciriani tried to realize a space continuum through the spatial expansion, openness and closeness by natural light and incorporate the architectural form, interior space and exhibition circulation with natural light in order to create innovative exhibition space in museum buildings.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.4
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• pp.437-444
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• 2004

To control algal bloom in reservoirs in Korea, artificial circulation systems have been applied. Diffuser block aeration systems have been increasingly used in Korean reservoirs especially for shallow ones. However, there has been no sound theoretical background for the design and operation of the system. Also there has not been sufficient post-installation studies to validate the effectiveness of the system. As a result, it has been repeatedly reported that the success of the system is not certain. Proper consideration on thermal stratification regimes of reservoirs and flow dynamics induced by bubble plumes are essential elements in design processes of the aeration system. This paper discusses the current methods in the design of diffuser type aeration system and suggests a new design method based on fluid mechanical theory. Example calculations were discussed using observed data of the Yeoncho Dam and it seems that the results represent the current situation successfully.

• Journal of Biomedical Engineering Research
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• v.19 no.1
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• pp.39-46
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• 1998

In this paper, we present a neural network identification and a control of highly complicated nonlinear left ventricular assist device(LVAD) system with a pneumatically driven mock circulation system. Generally, the LVAD system needs to compensate for nonlinearities. It is necessary to apply high performance control techniques. Fortunately, the neural network can be applied to control of a nonlinear dynamic system by learning capability. In this study, we identify the LVAD system with neural network identification(NNI). Once the NNI has learned the dynamic model of the LVAD system, the other network, called neural network controller(NNC), is designed for a control of the LVAD system. The ability and effectiveness of identifying and controlling the LVAD system using the proposed algorithm will be demonstrated by computer simulation.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.5
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• pp.19-27
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• 2016

This study is to find appropriate plant for infiltration swale (which is natural LID infrastructure) and suggest basic research database for building infrastructure of LID facilities. Through the research inside, it first selects the plant strong to flooding and salt tolerance. Also, the research built infiltration swale along the road, planted those strong plants and monitored how well those plants adapted into the environment. Particularly, it showered 72mm/hr-speed artificial shower, also with natural shower, given that plants were vulnerable to flood because of influx of the rain. As a result of field applicability monitoring, Pennisetum alopecuroides and Equisetum hyemale (which degrade the pollutant well and adapt into rainy environment) are planting individually, or Juncus effusus var. decipiens, Liriope platyphylla, Miscanthus sinensis Andersson, Euonymus japonica (which are strong to rainy environment) and Pennisetum alopecuroides and Equisetum hyemale are mixed planting. The research should have monitored the plant for more than one year to study them, but the research only lasted five months. Therefore, it is hard to generalize. After all, through the long term research, it should pursue study more on appropriate plant materials and database that can be the reference for infrastructure establishment and maintenance.

• Journal of The Korean Dental Society of Anesthesiology
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• v.6 no.2 s.11
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• pp.121-126
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• 2006

Generalized anaphylaxis is a most dramatic and acutely life-threatening allergic reaction. Most fatalities from anaphylaxis occur within the first 30 minutes postantigenic exposure. The mechanism of generalized anaphylaxis is the reaction of IgE antibodies to an allergen that causes the release of histamine, bradykinin, and others. These chemical mediators cause the contraction of smooth muscles of the respiratory and intestinal tracts, as well as increased vascular permeability. Four major clinical symptoms are recognized: skin reactions, smooth muscle spasm (gastrointestinal and genitourinary tracts and respiratory smooth muscle), respiratory distress, and cardiovascular collapse. Epinephrine is the drug of choice for the management. Its syrnpathomimetic effects directly counteract most aspects of the attack. Respiration must be immediately supported by the establishment of a patent airway along with artificial ventilation. The circulation should be supported and the existing hypotension overcome by placing the victim in a position to allow gravity to aid venous return and by administering intravenous fluids, vasopressors, and corticosteroids. When an imperceptible pulse is evident, external cardiac compression must also be instituted. This is a case report of anaphylactic shock care during general anesthesia, possibly due to penicillin, pancuronium and others.