• Steel and Composite Structures
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• 제34권4호
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• pp.511-524
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• 2020

In this research, a simple four-variable trigonometric integral shear deformation model is proposed for the static behavior of advanced functionally graded (AFG) ceramic-metal plates supported by a two-parameter elastic foundation and subjected to a nonlinear hygro-thermo-mechanical load. The elastic properties, including both the thermal expansion and moisture coefficients of the plate, are also supposed to be varied within thickness direction by following a power law distribution in terms of volume fractions of the components of the material. The interest of the current theory is seen in its kinematics that use only four independent unknowns, while first-order plate theory and other higher-order plate theories require at least five unknowns. The "in-plane displacement field" of the proposed theory utilizes cosine functions in terms of thickness coordinates to calculate out-of-plane shear deformations. The vertical displacement includes flexural and shear components. The elastic foundation is introduced in mathematical modeling as a two-parameter Winkler-Pasternak foundation. The virtual displacement principle is applied to obtain the basic equations and a Navier solution technique is used to determine an analytical solution. The numerical results predicted by the proposed formulation are compared with results already published in the literature to demonstrate the accuracy and efficiency of the proposed theory. The influences of "moisture concentration", temperature, stiffness of foundation, shear deformation, geometric ratios and volume fraction variation on the mechanical behavior of AFG plates are examined and discussed in detail.

• 한국식품영양학회지
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• 제35권5호
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• pp.324-331
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• 2022

Recently, consumers' awareness of the importance of the intestinal action of lactic acid bacteria and intestinal microbes is increasing, as well as interest in yogurt. In this study, yogurt was prepared with three mixed strains (lactic acid bacteria combination, Lactobacillus acidophilus, Lactobacillus delbrueckii subsp., and Bulgaricus, Streptococcus thermophilussei, 1:1:1) by adding oats flour, and the quality characteristics of yogurt were investigated, while stored at a storage temperature of 4℃ for 12 days. According to the storage period, the control as wel as the oat yogurt showed slight decrease in pH, and no significant change in acidity. Sugar content slightly increased. and brightness decreased, in the control and the oat yogurt. Visible cell numbers increased during storage, and decreased on the 12th day. Viscosity in the oat yogurt was 7,580 cP, which was approximately eight times higher than that of the control group, and decreased gradually according to the storage period. Antioxidant activity (DPPH) was approximately two times higher in the oat-added yogurt, and slightly increased with the storage period, decreased on the 12th day of storage, and β-glucan was detected only in oat-added yogurt.

• Structural Engineering and Mechanics
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• 제12권6호
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• pp.657-668
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• 2001

Fiber reinforced cementitious composites are nowadays widely applied in civil engineering. The postcracking performance of this material depends on the interaction between a steel fiber, which is obliquely across a crack, and its surrounding matrix. While the partly debonded steel fiber is subjected to pulling out from the matrix and simultaneously subjected to transverse force, it may be modelled as a Bernoulli-Euler beam partly supported on an elastic foundation with non-linearly varying modulus. The fiber bridging the crack may be cut into two parts to simplify the problem (Leung and Li 1992). To obtain the transverse displacement at the cut end of the fiber (Fig. 1), it is convenient to directly solve the corresponding differential equation. At the first glance, it is a classical beam on foundation problem. However, the differential equation is not analytically solvable due to the non-linear distribution of the foundation stiffness. Moreover, since the second order deformation effect is included, the boundary conditions become complex and hence conventional numerical tools such as the spline or difference methods may not be sufficient. In this study, moment equilibrium is the basis for formulation of the fundamental differential equation for the beam (Timoshenko 1956). For the cantilever part of the beam, direct integration is performed. For the non-linearly supported part, a transformation is carried out to reduce the higher order differential equation into one order simultaneous equations. The Runge-Kutta technique is employed for the solution within the boundary domain. Finally, multi-dimensional optimization approaches are carefully tested and applied to find the boundary values that are of interest. The numerical solution procedure is demonstrated to be stable and convergent.

• 대한임베디드공학회논문지
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• 제18권6호
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• pp.267-275
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• 2023

This paper presents the development of specialized software for annotating volume-of-interest on ¹⁸F-FDG PET/CT images with the goal of facilitating the studies and diagnosis of head and neck cancer (HNC). To achieve an efficient annotation process, we employed the SE-Norm-Residual Layer-based U-Net model. This model exhibited outstanding proficiency to segment cancerous regions within ¹⁸F-FDG PET/CT scans of HNC cases. Manual annotation function was also integrated, allowing researchers and clinicians to validate and refine annotations based on dataset characteristics. Workspace has a display with fusion of both PET and CT images, providing enhance user convenience through simultaneous visualization. The performance of deeplearning model was validated using a Hecktor 2021 dataset, and subsequently developed semi-automatic annotation functionalities. We began by performing image preprocessing including resampling, normalization, and co-registration, followed by an evaluation of the deep learning model performance. This model was integrated into the software, serving as an initial automatic segmentation step. Users can manually refine pre-segmented regions to correct false positives and false negatives. Annotation images are subsequently saved along with their corresponding ¹⁸F-FDG PET/CT fusion images, enabling their application across various domains. In this study, we developed a semi-automatic annotation software designed for efficiently generating annotated lesion images, with applications in HNC research and diagnosis. The findings indicated that this software surpasses conventional tools, particularly in the context of HNC-specific annotation with ¹⁸F-FDG PET/CT data. Consequently, developed software offers a robust solution for producing annotated datasets, driving advances in the studies and diagnosis of HNC.

• 한국항공운항학회지
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• 제17권2호
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• pp.52-61
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• 2009

In Korea, there is great lack in jet lease agreements compared to many other countries. Due to such scarcity in numbers of jet lease agreements, problems have never truly surfaced and legal foundation dealing with such issues have not yet been formulated. However, as the globalization is making the world smaller and smaller, the demand for jets will grow. As the Korean aviation industry is expanding tremendously, although very preliminary at this time, the interest and actual execution on private jet lease agreements will grow. The prediction of increase in the private jet ownership is causing the lease industry to be nervous and may require particular preparatory foundation works. Particularly, legal analysis and detailed review maybe necessary to set a precedent with will serve as the grounded rule in the future. It is notable that Vietnam, a country which is believed have a less developed aviation industry than Korea, had already established a specialized jet leasing company, VALC in 2007. Also, when leasing an airplane from a foreign financial institution, it is possible to obtain a government issued guarantee. Therefore, it is urgent for Korea to prepare the legal foundation for the future demands in aviation leasing, as well as private jet leases which in turn would promote national wealth and further develop the financial industry.

• Journal of Ecology and Environment
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• 제47권2호
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• pp.27-34
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• 2023

Background: The understanding of ecosystem services can be quantified and qualitative to assess the impacts of changes in the ecosystem to support human well-being. In the Democratic People's Republic of Korea, sustainable use of ecosystem services has attracted the interest of a range of decision-makers. However, although there is a concern for biodiversity, natural ecosystem, and their services, linking ecosystems with conservation planning remains challenging. Results: This study assessed the first qualitative ecosystem services provided by the Mundok wetland with decision makers of the West/Yellow Sea region. Furthermore, this study applied the Rapid Assessment Wetland Ecosystem method to support natural resources management, improving living conditions. We identified that cultural and supporting services index are highly provided, but preparing a plan to increase the provisioning and regulating services in Mundok wetland is necessary. Conclusions: The assessment results can provide helpful information for ecosystem services assessment, habitat conservation, conservation planning, and decision-making at local level.

• 한국도서관정보학회지
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• 제39권3호
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• pp.267-297
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• 2008

이 연구는 근현대 독서 대중화 운동을 전반적으로 검토하기 위한 한 과정으로서, 2000년대 독서운동과 독서교육의 양상을 고찰하는 데 목적을 두었다. 그간 근대 독서가 시작된 1920년대부터 1990년대까지의 독서 운동과 독서교육에 관하여 고찰한 바 있으며 본고는 그 후속 연구에 속한다. 본고에서는 2000년대의 독서현상을 전 시기의 독서 현상과 비교 분석하여, 그 특징적인 면을 도출해 내고 독서운동과 독서교육의 현주소를 찾아보려는 데 목적을 두었다. 이러한 연구 목적을 염두에 두면서 본론에서는 첫째, 독서운동으로 1) 도서관과 공공기관의 독서운동, 2) 서점 및 매체, 각종 단체의 독서운동, 3) 학생 독서운동과 학교 독서교육 등으로 나누어 고찰하였으며, 둘째, 독서경향은 1) 일반 독서경향, 2) 학생 독서경향으로 대별하여 그 특징적인 경향을 살폈다. 독서운동과 독서경향에 대한 이러한 분석은 향후 독서교육 및 독서 대중화 운동을 효과적으로 전개시키는 토대로 작용할 것이다.

• 공학교육연구
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• 제22권6호
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• pp.21-27
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• 2019

In the last few years, interest in computer science education has increased significantly. The curriculum is being revised to introduce computer science. Although interest has focused on coding as the main subject, in fact the computer science includes much more than coding. It engages people in being creative with technology as well as understanding the fundamental principles of computer science. Therefore, it is important to consider the curriculum to provide a foundation by teaching and learning computer science. The curriculum is required the development of courses to teach computer science for non-majors in general education. To think like a computer scientist on the knowledge of computer science is computational thinking. In order to maximize the effectiveness of teaching and learning for computational thinking, various teaching methods and supplementary learning materials, and activities should be developed and provided.

• Journal of the Korean Statistical Society
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• 제36권1호
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• pp.77-91
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• 2007

This paper considers development of noninformative priors for the familial data when the families have equal number of offspring. Several noninformative priors including the widely used Jeffreys' prior as well as the different reference priors are derived. Also, a simultaneously-marginally-probability-matching prior is considered and probability matching priors are derived when the parameter of interest is inter- or intra-class correlation coefficient. The simulation study implemented by Gibbs sampler shows that two-group reference prior is slightly edge over the others in terms of coverage probability.

• Journal of Applied and Pure Mathematics
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• 제5권5_6호
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• pp.407-414
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• 2023

In this article we continue the study of smooth Picard singular integral operators that started in [2], see there chapters 10-14. This time the foundation of our research is a trigonometric Taylor's formula. We establish the convergence of our operators to the unit operator with rates via Jackson type inequalities engaging the first modulus of continuity. Of interest here is a residual appearing term. Note that our operators are not positive. Our results are pointwise and uniform.