• International journal of steel structures
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• v.18 no.5
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• pp.1577-1588
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• 2018

As the excellent mechanical performance and easy construction of concrete filled steel tubes (CFST) composite structure, it has the potential to be used to strengthen RC pier columns. Therefore, tests were conducted on 2 reinforcement concrete (RC) stub columns and 9 RC columns strengthened with circular CFST under axial loading. The test results show that the circular CFST strengthening method is effective since the mean bearing capacity of the RC columns is increased at least 3.69 times and the ductility index is significantly improved more than 30%. One of the reasons for enhancement is obvious confinement provided by steel tube besides the additional bearing capacity supplied by the strengthening materials. From the analysis of the enhancement ratio, the strengthening structure has at least an extra 20% amplification except for taking full advantage of the strength of the strengthening material. Through the analysis of confining stress provided by steel tube and the stress-strain relationship of confined concrete, it is found that the strength of the core concrete can be increased by 21-33% and the ultimate strain can be enhanced to beyond $15,000{\mu}{\varepsilon}$.

• Journal of Korea Multimedia Society
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• v.25 no.2
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• pp.166-175
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• 2022

Digital transformation is driving so many changes in daily life and industry. The automobile industry is in a similar situation. In some cases, element techniques in areas called metabuses are also being adopted, such as 3D animated digital cockpit, around view, and voice AI, etc. Through the growth of the mobile market, the norm of human-computer interaction (HCI) has been evolving from keyboard-mouse interaction to touch screen. The core area was the graphical user interface (GUI), and recently, the audio user interface (AUI) has partially replaced the GUI. Since it is easy to access and intuitive to the user, it is quickly becoming a common area of the in-vehicle experience (IVE), especially. The benefits of a AUI are freeing the driver's eyes and hands, using fewer screens, lower interaction costs, more emotional and personal, effective for people with low vision. Nevertheless, when and where to apply a GUI or AUI are actually different approaches because some information is easier to process as we see it. In other cases, there is potential that AUI is more suitable. This is a study on a proposal to actively apply a AUI in the near future based on the context of various scenes occurring to improve IVE.

• Smart Structures and Systems
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• v.30 no.6
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• pp.557-569
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• 2022

Vibration-based structural health monitoring (SHM) is crucial for the dynamic maintenance of civil building structures to protect property security and the lives of the public. Analyzing these vibrations with modern artificial intelligence and deep learning (DL) methods is a new trend. This paper proposed an unsupervised deep learning method based on a convolutional autoencoder (CAE), which can overcome the limitations of conventional supervised deep learning. With the convolutional core applied to the DL network, the method can extract features self-adaptively and efficiently. The effectiveness of the method in detecting damage is then tested using a benchmark model. Thereafter, this method is used to detect damage and instant disaster events in a rubber bearing-isolated gymnasium structure. The results indicate that the method enables the CAE network to learn the intact vibrations, so as to distinguish between different damage states of the benchmark model, and the outcome meets the high-dimensional data distribution characteristics visualized by the t-SNE method. Besides, the CAE-based network trained with daily vibrations of the isolating layer in the gymnasium can precisely recover newly collected vibration and detect the occurrence of the ground motion. The proposed method is effective at identifying nonlinear variations in the dynamic responses and has the potential to be used for structural condition assessment and safety warning.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.171-171
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• 2023

This study investigates the capability of Physics-Informed Neural Networks (PINNs) for solving the solution of partial differential equations. Particularly, the 1D Saint-Venant Equations (SVEs) were considered, which describe the movement of water in a domain with shallow depth compared to its horizontal extent, and are widely adopted in hydrodynamics, river, and coastal engineering. The core contribution of this work is to combine the robustness of neural networks with the physical constraints of the SVEs. The PINNs method utilized a neural network to approximate the solutions of SVEs, while also enforcing the underlying physical principles of the equations. This allows for a more effective and reliable solution, especially in areas with complex geometry and varying bathymetry. To validate the robustness of the PINNs method, numerical experiments were conducted on several benchmark problems. The results show that the PINNs could be achieved high accuracy when compared with the solution from the numerical solution. Overall, this study demonstrates the potential of using PINNs and highlights the benefits of integrating neural network and physics information for improved efficiency and accuracy in solving SVEs.

• Research in Community and Public Health Nursing
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• v.28 no.3
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• pp.347-356
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• 2017

Purpose: The purpose of this study was to provide basic evidence to improve community health nursing practice education by analyzing the current status of actual operation, program outcomes and evaluation methods, and the level of achieving learning goals. Methods: Data were collected through an e-mail survey from 155 professors teaching community health nursing in April 2016. Out of 45 responses in total, 42 cases were used for analysis (response rate 29.0%). Results: Community health nursing practice was a 3-credit course in most of the schools (66.7%) and included a practice at public health centers without exception. The most common diagnosis classification system was OMAHA (81.0%). The core fundamental nursing skills evaluated during the practice were subcutaneous injection, vital signs, oral administration, and intradermal injection. Among the subjects of community health nursing practice, the area with the highest potential for achieving learning goals was primary health care provision (4.4/5) and the area with the lowest potential was disaster management (2.4/5). Conclusion: The results of this study show that there would be active efforts to complement and improve several problems of the community health nursing practice among the community health nursing practice instructors for more effective and qualitative community health nursing practice.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1447-1452
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• 2012

Aim: To evaluate the differential diagnostic potential of lesion stiffness assessed by the sonoelastographic strain index ratio (SR) and elastographic color scoring system (UE) for breast lesions. Materials and Methods: Three hundred and forty two breast masses (158 benign and 184 malignant) from 325 consecutive patients (mean age 44.2 years; range 16-81)who had been scheduled for a sonographically guided core biopsy were examined proposed by Itoh et al, with scoring 1-3=benign and 4-5=malignant. Strain and area ratios of each lesion were calculated within the same machine. Histological diagnosis was used as the reference standard. The area under the curve (AUC) and cut-off point were obtained by receiver operating curve and the cross table Fischer Test was carried out for assessing diagnostic value. Sensitivity, specificity, PPV, NPV, accuracy and false-discovery rates were compared. Results: The mean strain ratios for benign and malignant lesions were 1.87 and 7.9 respectively. (P<0.0001). When a cutoff point of 3.54 was used, SR had a sensitivity of 94.6%, a specificity 94.3%, a PPV of 95.1%, an NPV of 93.7% and an accuracy of 94.4%. The AUC values were 0.90 for the 5 point scoring system (UE) and 0.96 for the strain index ratio. The overall diagnostic performance was SR method was better (P<0.05). Conclusions: Strain ratio measurement could be another effective predictor in elastography imaging besides 5 the point scoring system for differential diagnosis of breast lesions.

• International Journal of Stem Cells
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• v.16 no.1
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• pp.1-15
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• 2023

Liver organoids have gained much attention in recent years for their potential applications to liver disease modeling and pharmacologic drug screening. Liver organoids produced in vitro reflect some aspects of the in vivo physiological and pathological conditions of the liver. However, the generation of liver organoids with perfusable luminal vasculature remains a major challenge, hindering precise and effective modeling of liver diseases. Furthermore, vascularization is required for large organoids or assembloids to closely mimic the complexity of tissue architecture without cell death in the core region. A few studies have successfully generated liver organoids with endothelial cell networks, but most of these vascular networks produced luminal structures after being transplanted into tissues of host animals. Therefore, formation of luminal vasculature is an unmet need to overcome the limitation of liver organoids as an in vitro model investigating different acute and chronic liver diseases. Here, we provide an overview of the unique features of hepatic vasculature under pathophysiological conditions and summarize the biochemical and biophysical cues that drive vasculogenesis and angiogenesis in vitro. We also highlight recent progress in generating vascularized liver organoids in vitro and discuss potential strategies that may enable the generation of perfusable luminal vasculature in liver organoids.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.2
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• pp.39-49
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• 2002

The purpose of this study is to propose an objective and rational methodology for the selection of proposed sites far the National Trust(NT), which is the new alterative proposal far the conservation of natural environments destroyed by injudicious land development and economic growth. That is to enforce many analysis for the effective estimation of rare ecological and landscape resources and to propose a model based on estimation and united indicators. Using the estimative model, we apply it to the selection of the proposed site in micro scale and simultaneously offer the basic methodology of effective and systematic land conservation in macro scale. The results of this study are as follows: 1) The results of analysis for the reliability of estimative items and indicators, presented no problem in that the coefficient of reliability was over 0.7. 2) The correlation measure of the estimative indicator indicated that 'succession'and 'regenerating restorability' were highly correlative in the item of plants. Another three items showed a tendency to be alike. 3) The results of factor analysis on the characteristics of indicators, classified plants into four categories including a stable factor. The item of animals was classified as a stable and rare factor. The item of landscape was classified as a physical and mental factor and the environment as a pollutional and conditional factor. 4) The model of estimation created through factor analysis was valid for the approval of the regression model because significant probability was 0.00. When we consider the NT proposed site as a complex body that is composed of diverse natural and manmade resources, certainly the synthetic methodology of estimation is needed. If these studies are carried out, NT sites will be selected more rationally and effectively than at present. Consequently, they have the potential to play a core role of natural ecosystem conservation in Korea.

• Journal of The Korean Association For Science Education
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• v.32 no.8
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• pp.1356-1366
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• 2012

As the recent demand for human resources in science, technology, engineering, and mathematics (STEM), the development of professional STEM teacher is called worldwide. It is becoming a critical need in teacher education in order to educate student teachers, and prepare pre-service and beginning teachers for high quality of teaching competency. To promote the competency for $21^{st}$ century STEM teachers, the epistemology of technological pedagogical content knowledge (TPACK) is currently considered as the essential qualities of knowledge for highly qualified teachers. The aim of this study is explore the effect of case-based learning approach on TPACK competency of pre-service STEM teachers. In order to develop the pre-service teachers' competency regarding effective integration of technologies into teaching specific content areas, a series of innovative case study teaching in science and mathematics was presented to 43 participants of pre-service physics, chemistry, biology, mathematics, and computer teachers during a course of information and communication technology (ICT) in Education at Khon Kaen University, Thailand. After finishing a case presentation, the pre-service teachers were encouraged into a forum of critical open discussion by considering the potential impact of the case and the TPACK framework. They were investigated instructional design competency of using ICT tools into student learning process and their personal beliefs about ICT in educational process both before and after. The participant's reactions and learning was evaluated by using a self-reported questionnaire and an implementation log of content-specific learning process design, respectively. Results showed a change of their beliefs and the transformation of their TPACK competency in STEM teaching. In an effort to better serve the needs of high quality STEM teachers, the results of this study illustrated that the competency of TPACK could be particularly considered as a core attributes for future STEM teachers. By the way, case-based learning approach can play an effective part in preparing and professing the TPACK competency for STEM teachers.

• Journal of Internet Computing and Services
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• v.17 no.3
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• pp.33-43
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• 2016

In this study, 3D-image based course material has been suggested as a potential pedagogical tool for laboratory courses for aviational maintenance in vocational high schools. With a special focus on assembly/disassembly of the combustion chamber, 3D contents described here are created by Soildworks 2014 based on the textbook widely used in aviational high schools. By analyzing several textbooks currently adopted at various schools, we have clearly shown that the current text-based teaching method is far from being effective regarding providing adequate learning environment for high school students who study aviational maintenance. From the analysis of the conventional textbooks, it is seen that it is urgent that we should come up with more effective and efficient way of teaching methods for these topics at vocational high schools. Using Solidworks, we have developed very vivid 3D image-based course material for topics related to a combustion chamber in the airplane. Newly developed 3D material is seen to clearly show step by step procedures of assembly and disassembly of the combustion chamber which has crucial importance in the aviational laboratory courses. Especially the transparent feature in Solidworks could make it possible to observe the parts covered by outer casing, which can not be seen even in any laboratory class with real objects. 3D animated views could provided unprecedented learning environment for students to acquire core knowledge with ease for the maintenance of a combustion chamber. In order to provide easy access for students to this 3D-based course material, the exclusive viewer is also developed using MS office powerpoint 2007. An example of a learning plan using 3d course material is suggested as well.