• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.1
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• pp.9-18
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• 2023

Predicting the compressive strength of high-performance concrete (HPC) is challenging because of the use of additional cementitious materials; thus, the development of improved predictive models is essential. The purpose of this study was to develop an HPC compressive-strength prediction model using an ensemble machine-learning method of combined bagging and stacking techniques. The result is a new ensemble technique that integrates the existing ensemble methods of bagging and stacking to solve the problems of a single machine-learning model and improve the prediction performance of the model. The nonlinear regression, support vector machine, artificial neural network, and Gaussian process regression approaches were used as single machine-learning methods and bagging and stacking techniques as ensemble machine-learning methods. As a result, the model of the proposed method showed improved accuracy results compared with single machine-learning models, an individual bagging technique model, and a stacking technique model. This was confirmed through a comparison of four representative performance indicators, verifying the effectiveness of the method.

• BMB Reports
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• v.56 no.4
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• pp.234-239
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• 2023

Thioredoxin-like protein 1 (TXNL1), one of the thioredoxin superfamily known as redox-regulator, plays an essential in maintaining cell survival via various antioxidant and anti-apoptotic mechanisms. It is well known that relationship between ischemia and oxidative stress, however, the role of TXNL1 protein in ischemic damage has not been fully investigated. In the present study, we aimed to determine the protective role of TXNL1 against on ischemic injury in vitro and in vivo using cell permeable Tat-TXNL1 fusion protein. Transduced Tat-TXNL1 inhibited ROS production and cell death in H₂O₂-exposed hippocampal neuronal (HT-22) cells and modulated MAPKs and Akt activation, and pro-apoptotic protein expression levels in the cells. In an ischemia animal model, Tat-TXNL1 markedly decreased hippocampal neuronal cell death and the activation of astrocytes and microglia. These findings indicate that cell permeable Tat-TXNL1 protects against oxidative stress in vitro and in vivo ischemic animal model. Therefore, we suggest Tat-TXNL1 can be a potential therapeutic protein for ischemic injury.

• Korean Journal of Animal Reproduction
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• v.25 no.4
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• pp.389-397
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• 2001

Cocaine-amphetamine regulated transcript (CART), a satiety factor regulated by leptin, is associated with food intake and motor behavior. In knock out studies, Leu34Phe mutation of human CART gene resulted in obese phenotype but mice carrying a targeted deletion of the CART gene exhibited no dramatic increase of body weight on normal fat diet. To establish a new transgenic mouse model for determining the function of CART on feeding behavior in vivo, we constructed the fusion gene, CART gene under the control of neurofilament light chain promoter, which regulates gene expression at the stage of neuronal differentiation. Transgenic mice were generated by microinjection method and screened by PCR and Southern blot analyses. In these transgenic mice, overexpression of CART was detected by in situ hybridization in spinal cords and brains at 13.5 days post-coitum embryos. At six weeks of age, RT-PCR analysis showed that exogenous CART mRNA was expressed strongly in brains and spinal cords, but not much in other tissues. Our results suggest that these transgenic mice provide a new model to investigate the function of CART gene in neuronal network associated with feeding behavior.

• Korean Journal of Animal Reproduction
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• v.24 no.4
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• pp.429-437
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• 2000

This study investigated the successful introduction of genes of erythropoietin (EPO) and enhanced green fluorescent protein (EGFP) in bovine embryos following nuclear transfer of bovine fetal fibroblasts (bFF), which were transfected by retrovirus vector system. Non-starved bFF were, transferred into perivitelline space of enucleated oocytes. The bFF-oocyte units were accomplished by cell to cell fusion and activated with calcium inophore and 6-dimethylaminopurine. Reconstructed embryos were co-cultured with bovine oviduct epithelial cells in CRlaa medium for 8 days. Out of 187 (EPO) and 210 (EGFP) bovine eggs reconstructed by nuclear transfer, 149 (EPO : 80.0%) and 158 (EGFP : 75.2%) embryos were cleaved, and among them 36 (EPO : 24.2%) and 35 (EGFP : 22.2%) embryos developed to the blastocyst stage. Of these blastocysts, 100% integration of EPO gene in 36 embryos was determined by PCR, and 100% expression of EGFP gene in 35 embryos was observed under the fluorescent microscope. This result indicates that bovine oocytes reconstructed by nuclear transfer of transfected bFF can successfully develop to the blastocyst stage. Furthermore, this novel procedure may be presumably an attractive method efficiently to produce the transgenic cattles.

• The Korean Journal of Nuclear Medicine Technology
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• v.27 no.1
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• pp.47-54
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• 2023

Purpose PET-CT imaging require an appropriate quality assurance system to achieve high efficiency and reliability. Quality control is essential for improving the quality of care and patient safety. Currently, there are performance evaluation methods of UN2-1994 and UN2-2001 proposed by NEMA and IEC for PET-CT image evaluation. In this study, we compare phantom images with the same experiments before and after PET-CT 3D normalization and well counter correction and evaluate the usefulness of quality control. Materials and methods Discovery 690 (General Electric Healthcare, USA) PET-CT equiptment was used to perform 3D normalization and well counter correction as recommended by GE Healthcare. Based on the recovery coefficients for the six spheres of the NEMA IEC Body Phantom recommended by the EARL. 20kBq/㎖ of ¹⁸F was injected into the sphere of the phantom and 2kBq/㎖ of ¹⁸F was injected into the body of phantom. PET-CT scan was performed with a radioacitivity ratio of 10:1. Images were reconstructed by appliying TOF+PSF+TOF, OSEM+PSF, OSEM and Gaussian filter 4.0, 4.5, 5.0, 5.5, 6.0, 6,5 mm with matrix size 128×128, slice thickness 3.75 mm, iteration 2, subset 16 conditions. The PET image was attenuation corrected using the CT images and analyzed using software program AW 4.7 (General Electric Healthcare, USA). The ROI was set to fit 6 spheres in the CT image, RC (Recovery Coefficient) was measured after fusion of PET and CT. Statistical analysis was performed wilcoxon signed rank test using R. Results Overall, after the quality control items were performed, the recovery coefficient of the phantom image increased and measured. Recovery coefficient according to the image reconstruction increased in the order TOF+PSF, TOF, OSEM+PSF, before and after quality control, RCmax increased by OSEM 0.13, OSEM+PSF 0.16, TOF 0.16, TOF+PSF 0.15 and RCmean increased by OSEM 0.09, OSEM+PSF 0.09, TOF 0.106, TOF+PSF 0.10. Both groups showed a statistically significant difference in Wilcoxon signed rank test results (P value<0.001). Conclusion PET-CT system require quality assurance to achieve high efficiency and reliability. Standardized intervals and procedures should be followed for quality control. We hope that this study will be a good opportunity to think about the importance of quality control in PET-CT

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.6
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• pp.63-72
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• 2017

This study made of centrally actual application in general arts classes based on movie in university. Especially, I analyzed the activities of the class with 'Untouchable: 1% friendship' among 6 films. The objects of this study are 44 students of D university in Busan Metropolitan City who take 'creative fusion from movie' general arts class which opened first semester in 2016. In this study, students were able to watch movies through the creative class, which was out of the traditional classroom method, and after 15 hours of learning the quiz online, they conducted 15 weeks as a teaching method to perform tasks, presentations, experiments, and experiences in regular class time. The results of this study are as follows. 'It is a general arts class that makes movements live,' 'It is a general arts class that shows movies from various perspectives,' and 'It is a general arts class that makes me know.' This suggests that the educational medium, which is easily accessible in everyday life, and the general arts class, which is active in the space outside the framework, are perceived as stimulating curiosity and adding fun to college students.

• Korea Science and Art Forum
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• v.27
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• pp.101-114
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• 2017

Based on the relationship between urban public space, urban lighting and the sense of place, this paper aims to analyze the lighting environment types with the sense of place and their characteristics. First, with the theory study as the research foundation, it extracts six spatial factors of public space lighting design and then analyzes 12 relevant cases on the basis. Finally, it divides the 12 cases into four types, Basic types, Storytelling, Interactive and Multi-Media and analyzes the core design factor and characteristics of various types. The results show that: first, functionality, sustainability and aesthetics are the basic factors to realize the urban public space lighting places. Second, the six cases of "Storytelling" show that the theme of specific areas, namely the exploration of "story" is conducive for lighting design to form clear and definite environment recognition. Third, for "Interactive" and "Multi-Media", the intervention of new media technology and new lighting way has made the wide expansion of urban lighting design connotation and extension. The research results show that strengthening the urban location performance by the lighting design could improve the city image, which provides the basis for the development of urban public space lighting design.

• Korea Science and Art Forum
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• v.23
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• pp.149-162
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• 2016

Here are background, method, scope, main contents of this research. As the interests increased in recent about the construction in complex and diverse areas, construction is locally connected to human life like to coexistence of the technology and culture. The local development should not be fragmentary construction to improve local recycling ability. Local society should be inherited by modern cultural perspective through a variety of local culture and coexistence. Effective decision making analysis is necessary to build a livable area with a combination of high-tech industry. For this reason, this paper will study the political analysis for decision making at the planning stage of construction in point of fusion of technology and culture by using unstructured data analysis. Conclusion is as in the following. Local planning stage of construction describes diverse meanings of intangible and intangible factors as political factor. Technology factors have various qualitative and quantitative factors in construction field. Understanding decision making at the planning stage of construction means not only visible 'technology factor' such as structure, method, shape, and so on, but also invisible 'culture factor' such as spirit of age, religion, learning, and life-style reflected in formation process of space, and insight of brain power about art.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.11
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• pp.933-940
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• 2017

The modern society is changing paradigm by the 4th industrial revolution. In these changes, the importance of geospatial information leading to the fusion and connection of persons and objects is increasing day by day. GNSS CORS(Continuously Operating Reference Station) plays a pivotal role in the geospatial information by providing basic data for surveying control points, mapping, navigation, geophysical research, and so on. On the other hand, the satellite surveying technologies are developing rapidly and it is necessary to investigate the status of the satellite surveying environment and search for future directions. In this study, the environment related to satellite survey by operation status of domestic and overseas CORS(Continuously Operating Reference Station) was tried to analyze. Through the research, The operation status of NGII and IGS CORS were presented. It was found that the availability ratio of multiple satellites to the CORS of NGII are lower than that of IGS CORS. Considering the improvement of positioning performance by using multiple GNSS, it is necessary to use multi-satellites in the future.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2139-2146
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• 2023

During reactor operation, the divertor must withstand unprecedented simultaneous high heat fluxes and high-energy neutron irradiation. The extremely severe service environment of the divertor imposes a huge challenge to the bonding quality of divertor joints, i.e., the joints must withstand thermal, mechanical and neutron loads, as well as cyclic mode of operation. In this paper, potassium-doped tungsten (KW) is selected as the plasma facing material (PFM), oxygen-free copper (OFC) as the interlayer, oxide dispersion strengthened copper (ODS-Cu) alloy as the heat sink material, and reduced activation ferritic/martensitic (RAFM) steel as the structural material. In this study, a vacuum brazing technology is proposed and optimized to bond Cu and ODS-Cu alloy with the silver-free brazing material CuSnTi. The most appropriate brazing parameters are a brazing temperature of 940 ℃ and a holding time of 15 min. High-quality bonding interfaces have been successfully obtained by vacuum brazing technology, and the average shear strength of the as-obtained KW/Cu and ODS-Cu alloy joints is ~268 MPa. And a fabrication route for manufacturing the flat-type divertor target based on brazing technology is set. For evaluating the reliability of the fabrication technologies under the reactor relevant condition, the high heat flux test at 20 MW/m² for the as-manufactured flat-type KW/Cu/ODS-Cu/RAFM mockup is carried out by using the Electron-beam Material testing Scenario (EMS-60) with water cooling. This paper reports the improved vacuum brazing technology to connect Cu to ODS-Cu alloy and summarizes the production route, high heat flux (HHF) test, the pre and post non-destructive examination, and the surface results of the flat-type KW/Cu/ODS-Cu/RAFM mockup after the HHF test. The test results demonstrate that the mockup manufactured according to the fabrication route still have structural and interfacial integrity under cyclic high heat loads.