• Advances in aircraft and spacecraft science
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• v.9 no.5
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• pp.415-431
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• 2022

Secondary flows have a huge impact on losses generation in modern low pressure gas turbines (LPTs). At design point, the interaction of the blade profile with the end-wall boundary layer is responsible for up to 40% of total losses. Therefore, predicting accurately the end-wall flow field in a LPT is extremely important in the industrial design phase. Since the inlet boundary layer profile is one of the factors which most affects the evolution of secondary flows, the first main objective of the present work is to investigate the impact of two different inlet conditions on the end-wall flow field of the T106A, a well known LPT cascade. The first condition, labeled in the paper as C1, is represented by uniform conditions at the inlet plane and the second, C2, by a flow characterized by a defined inlet boundary layer profile. The code used for the simulations is based on the Discontinuous Galerkin (DG) formulation and solves the Reynolds-averaged Navier-Stokes (RANS) equations coupled with the Spalart Allmaras turbulence model. Secondly, this work aims at estimating the influence of viscosity and turbulence on the T106A end-wall flow field. In order to do so, RANS results are compared with those obtained from an inviscid simulation with a prescribed inlet total pressure profile, which mimics a boundary layer. A comparison between C1 and C2 results highlights an influence of secondary flows on the flow field up to a significant distance from the end-wall. In particular, the C2 end-wall flow field appears to be characterized by greater over turning and under turning angles and higher total pressure losses. Furthermore, the C2 simulated flow field shows good agreement with experimental and numerical data available in literature. The C2 and inviscid Euler computed flow fields, although globally comparable, present evident differences. The cascade passage simulated with inviscid flow is mainly dominated by a single large and homogeneous vortex structure, less stretched in the spanwise direction and closer to the end-wall than vortical structures computed by compressible flow simulation. It is reasonable, then, asserting that for the chosen test case a great part of the secondary flows details is strongly dependent on viscous phenomena and turbulence.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.1
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• pp.33-43
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• 2023

Pathological wear across the entire dentition causes problems such as collapsed occlusal plane, reduced vertical dimension, anterior premature contact, inadequate anterior guidance, and tooth migration, thereby induce symptoms such as temporomandibular joint disorder, reduced masticatory efficiency, and tooth hypersensitivity. For the treatment of patients with excessive wear, evaluation of vertical dimension should be preceded along with analysis of the cause. The patient in this case was a 45-year-old female with a history of orthognathic surgery. Through clinical examination, radiographic examination, and model analysis, overall tooth wear, interdental spacing in the anterior maxillary region, retruded condylar position, and insufficient interocclusal space for prosthetic restoration were confirmed. Full mouth rehabilitation with increased vertical dimension was planned, the patient's adaptation to the new vertical dimension was evaluated with a removable occlusal splint and temporary prosthesis, and cross-mounting was performed based on the temporary restoration to fabricate the definitive zirconia prosthesis, maintaining the adjusted vertical dimension. It showed satisfactory functional and esthetic results through stable restoration of the occlusal relationship.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1111-1119
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• 2022

Tourism projects through islands in the waters of Sinan-gun became active, and as a result, a total of 13 marine bridges connecting islands were completed. However, the marine bridge constructed in the fairway is dangerous for traffic. Particularly, in the case of the marine bridge connecting two islands, the width of the fairway is extremely narrow, therefore the risk is higher. In this study, we evaluated the risk of collision between marine bridge piers and ships using the IALA Waterway Risk Assessment Program (IWRAP), a risk assessment model for port waterways, based on a maritime traffic survey on the coastal bridge in Sinan-gun. The results, indicated that No.1 Sinan bridge had the highest probability of collision and most of the transit ships were coastal passenger ships. In addition, No.1 Sinan bridge was the place where the most collision accidents occurred among the marine bridge piers in the target sea, and the cause this study was analyzed. An analysis of the satellite images of the sea environment of No.1 Sinan bridge using an image processing method, confirmed that obstacles that could not be seen in the chart existed nearby the bridge. As a result, traffic was observed to be concentrated in one direction, unlike two-way traffic, which is a method of inducing traffic of bridges to avoid obstacles. The risk cause analysis method using the image processing technique of this study is expected to be used as a basic research method for analyzing the risk factors of island bridge in the future.

• Journal of Nutrition and Health
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• v.56 no.2
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• pp.217-230
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• 2023

Purpose: The purpose of this study was to assess the diet intake status and quality of adults from North Korea who had lived in Seoul and Gyeonggi-do, using the nutrition quotient (NQ) for Korean adults. Methods: A number of 166 adults aged from 20 to 64 years were enrolled as study subjects. A structured questionnaire was used to collect information on their demographic characteristics, food consumption frequency, eating behaviors, and NQ. The NQ score was then used to measure the overall diet quality. The NQ score was composed of four major age-based categories. 'Balance', 'Diversity', 'Moderation', and 'Dietary behavior' were utilized as scores for measurements within each of the four categories. The scores for all four categories were summed up, resulting in the total NQ score. Participants' age groups were stratified by 20's, 30's, 40', and over 50's. A χ² test and generalized linear regression (GLM) model were used to assess a significance for difference of subject distribution in categorical and continuous variables in the food consumption frequency, eating behaviors, and NQ scores. Results: Participants in younger age groups were more likely to report consumption of ramyeon, fast food, sweet and greasy baked products, processed beverage, delivery food, and night snacks than the older age groups. Most importantly, participants in 20's age group were less likely to report the total NQ and moderation score than the 50's age group. Conclusion: In this study, the 20's age group displayed a lower NQ characteristic for an unbalanced diet. Therefore, it is imperative for adults from North Korea to be given individualized diet instructions along with nutritional education programs.

• Journal of Intelligence and Information Systems
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• v.29 no.1
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• pp.41-63
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• 2023

As the online e-commerce market growing, the need for a recommender system that can provide suitable products or services to customer is emerging. Recently, many studies using the sentiment score of online review have been proposed to improve the limitations of study on recommender systems that utilize only quantitative information. However, this methodology has limitation in extracting specific preference information related to customer within online reviews, making it difficult to improve recommendation performance. To address the limitation of previous studies, this study proposes a novel recommendation methodology that applies deep learning technique and uses various linguistic factors within online reviews to elaborately learn customer preferences. First, the interaction was learned nonlinearly using deep learning technique for the purpose to extract complex interactions between customer and product. And to effectively utilize online review, cognitive contents, affective contents, and linguistic style matching that have an important influence on customer's purchasing decisions among linguistic factors were used. To verify the proposed methodology, an experiment was conducted using online review data in Amazon.com, and the experimental results confirmed the superiority of the proposed model. This study contributed to the theoretical and methodological aspects of recommender system study by proposing a methodology that effectively utilizes characteristics of customer's preferences in online reviews.

• Explosives and Blasting
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• v.40 no.4
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• pp.15-26
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• 2022

With the recent increase in old and dangerous buildings, the demand for technology in the field of structure demolition is rapidly increasing. In particular, in the case of structures with severe deformation of damage, there is a risk of deterioration in stability and disaster due to changes in the load distribution characteristics in the structure, so rapid structure demolition technology that can be efficiently dismantled in a short period of time is drawing attention. However, structural deformation such as unauthorized extension or illegal remodeling occurs frequently in many old structures, which is not reflected in structural information such as building drawings, and acts as an obstacle in the demolition design process. In this study, as an effective way to overcome the discrepancy between the structural information of old structures and the actual structure, access to actual structures through 3D modeling was considered. 3D point cloud data inside and outside the building were obtained through LiDAR and drone photography for buildings scheduled to be blasting demolition, and precision matching between the two spatial data groups was performed using an open-source based spatial information construction system. The 3D structure model was completed by importing point cloud data matched with 3D modeling software to create structural drawings for each layer and forming each member along the structure slab, pillar, beam, and ceiling boundary. In addition, the modeling technique proposed in this study was verified by comparing it with the actual measurement value for selected structure member.

• Journal of Industrial Convergence
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• v.21 no.2
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• pp.43-52
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• 2023

This study was conducted to examine the relationship of the COVID-19-related anxiety, self-efficacy, resilience, and professional competence of nurses working in hospitals where COVID-19 patients are hospitalized. Additionally, this study attempted to identify factors that affect the professional competence of nurses. Using a cross-sectional descriptive study design, an online survey of 120 nurses working at hospitals where COVID-19 patients were hospitalized was conducted between February 9 and February 19, 2021. Pearson's correlations were used to assess correlations between the main variables, and stepwise multiple regression was used to identify factors influencing professional competence. Results of the study showed that the professional competence of nurses was positively correlated with self-efficacy (r=.58, p<.001) and resilience (r=.56, p<.001). The correlation between professional competence and COVID-related anxiety was not significant (r=-.03, p=.766). Factors affecting professional competence included self-efficacy (β=.36, p=.004) and resilience (β=28, p=.021). The model explained approximately 35% of the variance in nurse professional competence (F=33.65, p<.001). To fully demonstrate the professional competence of nurses during the COVID-19 pandemic, institution-based programs should be developed and applied to improve their self-efficacy and resilience. In order to prevent the burnout of nurses in the longer-than-expected COVID-19 pandemic, efforts and policies at the nursing organization level are needed to systematically manage and monitor self-efficacy and resilience of nurses.

• Journal of Physiology & Pathology in Korean Medicine
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• v.36 no.5
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• pp.187-192
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• 2022

The purpose of this study is to examine the effect of herbal medicine complex (HMC) containing Camellia sinensis L., Duchoesna chrysantha, Houttuynia cordata Thunberg, Poncirus trifoliata Rafinesque on skin inflammation and atopic dermatitis. First, we examined the anti-inflammatory effect of HMC in TNF-α induced human keratinocytes (HaCaT cell). Real-time PCR and western blotting were performed to evaluate the expression of inflammatory cytokines (e.g., iNOS, COX-2, IL-6, IL-8) mRNA and protein. Four-weeks old male NC/Nga mice were treated with 1% 2,4-dinitrochlorobenzene (DNCB) solution and used as an atopic dermatitis mice model. And, HMC (200 mg/kg or 400 mg/kg) was administered directly into the stomach of mice for 4 weeks, and blood or serum analysis, tissue staining were performed after oral gavage. As a result HMC inhibited the mRNA expression of iNOS, COX-2, IL-6, and IL-8, which had been increased by TNF-α in HaCaT cells. In addition, the protein expression was also significantly suppressed in the same way as the mRNA expression results. The in vivo experiment results showed that, HMC administration reduced thickening of the epidermis and infiltration of eosinophil into the skin stratum basale compared to DNCB treatment. In addition, HMC administration significantly reduced the inflammatory cytokines (IL-4, IL-5, IL-6, and IL-13) production and immunocyte (white blood cell, lymphocyte, neutrophil, and eosinophil) count compared to DNCB treatment. Moreover, the serum IgE and histamine level was decreased by HMC administration. These results suggest that HMC can be used as effective herbal medicine extract for skin inflammation and atopic dermatitis. And this study may contribute to the development of the herbal medicine-based drug for the treatment of skin inflammation and atopic dermatitis.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.1
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• pp.37-47
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• 2023

The black cutworm, Agrotis ipsilon (Hufnagel), is an important crop pest worldwide that feeds more than 80 plant species including cabbage, potato, maize, wheat and bean, and this moth is a typical pest attacking underground parts of crops. It has been known in farm booklets that the larvae of A. ipsilon overwinter in the soil in Korea, but no definitive data exist yet. This study was conducted to evaluate that the specific appearance time of A. ipsilon observed actually in the field could be explained when we assumed that this pest overwinters in a form of larvae or pupae. Degree day-based phenology models were applied for tracking forward or backward to find the predicted developmental stage which developed at a specific stage found in the field. As a result of the analysis, it was confirmed that an initial population could be established in a group that does not overwinter as larvae or pupae in Korea. In other words, the appearance of adults in early March to April could not be explained by the presence of domestic overwintering populations. Populations that overwinter as larvae or pupae in Korea were able to emerge as adults in June to July at the earliest. Therefore, the group of adults appearing in early spring is highly likely to be a population that migrated from outside Korea. Taken together, it was estimated that the colony of A. ipsilon in Korea would be formed by a mixture of a migrant population through long-distance migration and a overwintering population.

• Journal of the Korean Society of Earth Science Education
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• v.16 no.1
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• pp.56-71
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• 2023

The purpose of this study is to explore the role and effectiveness of argumentation structure and the developmental characteristics of science PCK with Earth science preservice teachers who used argumentation structure as a pedagogical reasoning tool. Since teachers demonstrate PCK in a series of pedagogical reasoning processes using argumentation structures, we explored the characteristics of future-oriented family resemblance-PCK shown by preservice science teachers using argumentation structures. At the end of the semester, we conducted in-depth interviews with 15 earth science preservice teachers who had experienced lesson design and teaching practice using the argumentation structure. Qualitative analysis including a semantic network analysis was conducted based on the in-depth interview to analyze the characteristics of preservice teachers' family resemblance-PCK. Results include that preservice teachers organized their classes systematically by applying the argumentation structure, and structured classes by differentiating argumentation elements from facts to conclusions. Regarding the characteristics of each component of the argumentation structure, preservice teachers had difficulty finding warrant, rebuttal, and qualifier. The area of PCK most affected by the argumentation structure is the science teaching practice, and preservice teachers emphasized the selection of a instructional model suitable for lesson content, the use of various teaching methods and inquiry activities to persuade lesson content, and developing of data literacy and digital competency. Discussed in the conclusion are the potential and usability of argument structure as a pedagogical reasoning tool, the possibility of developing science inquiry and reasoning competency of secondary school students who experience science classes using argumentation structure, and the need for developing a teacher education protocol using argumentation structure as a pedagogical reasoning tool.