• International Journal of Vascular Biomedical Engineering
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• v.1 no.1
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• pp.32-40
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• 2003

Axillo-bifemoral (Ax-Fem) bypass are now well accepted for bilateral iliac artery occlusion as the second best option. This extra-anatomical (unnatural) bypasses, however, have various hemodynamic liabilities affecting the patency. Hemodynamic conditions of each different type of Ax-Fem bypass were assessed with computer simulation model to determine the hemodynamically more sound type. Simulation models of five different types of Ax-Fem bypass were constructed. Our investigation based on the computer simulation models have shown distinct differences between two most popular Lazy-S type and Inverted-C type on the distribution of flow volume, shear stress and recirculation zone, etc., though both types have shown similar clinical results. Lazy-S type has shown better hemodyanmic status than inverted-C type. The theoretical advantage of "Lazy-S" type has never been adequately proved for its superiority clinically over the inverted-C type. Inverted-C type is now in more favor with clinically better results in spite of many hemodynamic liabilities including retrograde flow to the branching graft. The improvement of over-all long-term patency rate of various extra-anatomical bypasses is still warranted through proper correction of the hemodynamic liability. Even though clinical outcome of the extra-anatomical bypass has been equal regardless of the type of crossover femoral graft configuration, there are distinct differences on the hemodynamic characteristics among various types of configuration. Further hemodynamic study in the pulsatile flow status is warranted to correct hemodynamic defects with proper modification of various hemodynamic factors of each model.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.57-60
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• 1995

The objective of this investigation is to understand the role of hemodynamics in the formation and development of atherosclerosis lesions in the human left coronary artery This study also aims to compare the blood flow characteristics of steady and physiological flows. Three dimensional, steady and physiological flows of blood in the left coronary artery are simulated using the Finite Volume Method. Apparent viscosity of blood is represented as a function of shear rate by the Carreau model. Distributions of velocity, pressure and shear stress in tile left coronary artery bifurcation are presented to compare tile steady and physiological flow characteristics.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.5
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• pp.459-464
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• 2010

Computer programs are required from all areas in society including machine, space, aviation, and medicine. However, the programming curriculum is getting hard despite a lot of teaching materials and video lessons. Programming languages are very diverse, but most of them use the same structure, and they only have different expression methods. Therefore, if one learns one programming language, then it doesn't need to spend a lot of time and efforts to learn another programming langue. Most programming languages use the structure of sequence, selection, and repletion in general. The important thing for programming learners is the structure or algorithm of programming not the grammar of program. This study designed and implemented the language learning system to learn structured programming by using a flowchart.

• Korean Journal of Radiology
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• v.23 no.3
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• pp.343-354
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• 2022

Objective: To develop and evaluate a deep learning-based artificial intelligence (AI) model for detecting skull fractures on plain radiographs in children. Materials and Methods: This retrospective multi-center study consisted of a development dataset acquired from two hospitals (n = 149 and 264) and an external test set (n = 95) from a third hospital. Datasets included children with head trauma who underwent both skull radiography and cranial computed tomography (CT). The development dataset was split into training, tuning, and internal test sets in a ratio of 7:1:2. The reference standard for skull fracture was cranial CT. Two radiology residents, a pediatric radiologist, and two emergency physicians participated in a two-session observer study on an external test set with and without AI assistance. We obtained the area under the receiver operating characteristic curve (AUROC), sensitivity, and specificity along with their 95% confidence intervals (CIs). Results: The AI model showed an AUROC of 0.922 (95% CI, 0.842-0.969) in the internal test set and 0.870 (95% CI, 0.785-0.930) in the external test set. The model had a sensitivity of 81.1% (95% CI, 64.8%-92.0%) and specificity of 91.3% (95% CI, 79.2%-97.6%) for the internal test set and 78.9% (95% CI, 54.4%-93.9%) and 88.2% (95% CI, 78.7%-94.4%), respectively, for the external test set. With the model's assistance, significant AUROC improvement was observed in radiology residents (pooled results) and emergency physicians (pooled results) with the difference from reading without AI assistance of 0.094 (95% CI, 0.020-0.168; p = 0.012) and 0.069 (95% CI, 0.002-0.136; p = 0.043), respectively, but not in the pediatric radiologist with the difference of 0.008 (95% CI, -0.074-0.090; p = 0.850). Conclusion: A deep learning-based AI model improved the performance of inexperienced radiologists and emergency physicians in diagnosing pediatric skull fractures on plain radiographs.

• Korean journal of aerospace and environmental medicine
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• v.31 no.1
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• pp.24-30
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• 2021

Purpose: The purpose of this study is to consider ways to strengthen it through comparison and curriculum while recognizing the importance of global competencies in liberal arts education in universities. Methods: In order to explore ways to reinforce the sub-competence of global competencies, this study was conducted at a four-year university in Chungcheong-do for one year in 2019, such as 'Global Culture Talk', 'Global Travel', 'Global Nanta', and 'Making Global Friends'. Cases of comparison and application of educational programs were analyzed. The program was attended by the Department of Business Administration, Department of Aviation Service, Department of Design, Department of Manga Animation, Department of Broadcasting and Film, and foreign exchange students. The competency-centered curriculum not only has clear educational goals, but is also very advantageous in establishing a feedback system by measuring its performance. This study will assess the effectiveness of the education plan by diagnosing the change in competencies before and after the comparison and curriculum is operated. Results: The overall global competency has increased by 0.2 points compared to 2017. By subsector, it was found that the flexibility increased by 1.4 points. In the field of cross-cultural understanding, it rose 0.6 points, and in the field of global understanding, it rose 2.2 points, showing the largest increase in the sub-fields. Nevertheless, the field of global interest remains at a low level. This is considerably low compared to flexibility and ability to understand other cultures, and it is expected that measures for improvement should be continuously sought. Since the understanding of other cultures has already exceeded 60 points, it is expected that the global competency of the university will be strengthened if the level is consistently maintained and the emphasis is placed on enhancing flexibility and improving global understanding. Conclusion: The importance of strengthening global capabilities is steadily rising. Universities are also reorganizing the curriculum by analyzing the needs and satisfaction of education consumers to respond to this. The programs operated and analyzed in this study were also made as part of this effort. However, since there are various factors that affect global competency, it cannot be but admitted that it is not easy to gauge the change in competency with only a few programs and short-term efforts. However, if the efforts pursued by this study are accumulated and supplemented through feedback from a long-term perspective, it can be expected that there are not a lot of contributions to strengthening global competencies in liberal arts education.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.5
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• pp.2239-2244
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• 2014

Objective: To investigate the effects of secondary left-sided portal hypertension (LSPH) on the radical operation rate of patients with pancreatic cancer and systemically evaluate the prognosis of patients with LSPH secondary to pancreatic cancer after radical surgery. Materials and Methods: The data of patients with pancreatic cancer who underwent laparotomy over a 15-year period in Department of Hepatobiliary Surgery of Chinese PLA Air Force General Hospital from Jan. 1, 1997, to Jun. 30, 2012 was retrospectively reviewed. Results: A total of 362 patients with pancreatic cancer after laparotomy were selected, including 73 with LSPH and 289 without LSPH. Thirty-five patients with LSPH (47.9%) and 147 without non-LSPH (50.9%) respectively underwent radical operations. No significant difference was found between these two groups regarding the total resection rate and stratified radical resection rate according to different pathological types and cancer locations. The mean and median survival time of patients after radical operation in LSPH group were $13.9{\pm}1.3$ months and 14.8 months, respectively, while those in non-LSPH group were $22.6{\pm}1.4$ months and 18.4 months, respectively(P<0.05). Conclusions: Radical operations for pancreatic cancer and secondary LSPH are safe and effective. Because high-grade malignancy and poor prognosis are closely associated, the decision for radical surgery should be made more meticulously for the patients with pancreatic cancer.

• Journal of Digital Contents Society
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• v.18 no.2
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• pp.393-401
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• 2017

As the importance of software in various industry areas has been increased, the number of accidents related to software safety are growing up. The key industries such as railroads, aviation and medicine, recommend IEC 61508 and international safety standards for their own to achieve functional safety and reduce the issues caused by that. For equipment of ship navigation, there are not any particular standards or guidance which Korean users can introduce as considering software functional safety. This article defines the procedure and outcomes of the risk analysis in order to secure software functional safety in marine navigational equipment and applies them to an echo sounder as a case study.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.167-169
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• 2021

There are only 14 public medical facilities available to residents regularly in the island area of Chungcheongnam-do, one health life support center, and one hospital ship, and these facilities and equipment cannot effectively respond to emergency patients such as severe trauma, cerebrovascular and cardiovascular diseases. The fastest means of transporting emergency patients is to use a doctor helicopter deployed at Dankook University Hospital (based in Cheonan). However, there is only one doctor helicopter deployed, and it cannot operate at night, and since it is in charge of all areas of Chungcheongnam-do, there is a limit to rapid transport in the event of a large number of patients. Therefore, we would like to review the necessity of "Chungnam-type Doctor UAM Development" to compensate for the problems of the urban aviation mobility (UAM) industry and the emergency patient transport system in islands, a field of the 4th industry.