• Magazine of the Korea Concrete Institute
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• v.8 no.6
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• pp.151-161
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• 1996

Recently, polypropylene fiber reinforced mortar and concrete as civil and architectural materials have been used in major countries in the world. Polypropylene fiber reinforced concrete has many advantages in terms of economical aspect, chemical stability and durability. It has been reported that polypropylene fiber can control restrained tensile stresses and cracks and increase toughness, resistance to impact, corrosion, fatigue and durability. The purpose of the present study is, therefore, to investigate the strength as well as many mechanical characteristics including toughness and shrinkage control properties. A specially devjsed shrinkage test has been applied to measure the crack control characteristics of polypropylene fiber reinforced concrete. The present study indicates that the polypropylene fiber reinforced concrete curbs greatly the crack occurrence due to shrinkage and enhances toughness resistance. The present study provides a firm base for the efficient use of polypropylene fiber reinforced concrete in actual construction such as pavements and slab structures.

• Journal of Navigation and Port Research
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• v.31 no.10
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• pp.905-910
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• 2007

As the ship is getting bigger and faster lately, ship's structure or cargoes might be often damaged and the ship might be cut in two in extreme conditions by a wave impact on its bow. In this paper, the vertical acceleration, which is one of factors for evaluating seakeeping performance, was measured under the various sea states by the hull stress monitoring system(HMS) on the bridge, and the result was compared with those of model test and theoretical studies. Then, we confirmed the seakeeping performance of T.S. HANBADA by comparing it with ITTC seakeeping criteria This result will be a great help for the safe navigation by making it possible to estimate the possibility of work and the amount of risk under the various sea conditions with which may be confronted, and the shipbuilding yard can be possible to construct the vessel with superior performance through these data measured on the actual ship.

• Journal of the Korean Society for information Management
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• v.27 no.4
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• pp.239-258
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• 2010

The purpose of this study is to develop a prediction model of patent citation counts based on major factors which affect patent citation. To this end, we performed multiple regression analysis between the patent citation counts and five explanatory variables such as the number of pages, the number of claims, the reference-average-citation rate, the strength of bibliographic coupling, and the document similarity proved as having 5% or more standardized variances($r^2$) with patent citation counts, with a test dataset of U.S. patents in five subject fields. As a result, our prediction models showed 58.3% to 89.6% predictability depending on subject fields and revealed the document similarity has the highest impact on citation counts among the five predictive variables in all the subject fields. The result of comparison between the predicted citation counts and the actual ones confirmed the usefulness of the citation prediction models built for each subject field.

• The KIPS Transactions:PartD
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• v.16D no.1
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• pp.43-54
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• 2009

The purpose of this study is to explore variables that affect users' perceived value of mobile advertising and actual response intention and to analyze causal relationships among variables. In order to verify the relational significance, we built new research model and hypotheses based on the Ducoffe's model(1996). And we found out four independent variables such as entertainment, information usefulness, convenience, economical efficiency, and advertising impact's value as a mediating variable. Especially, we classified into four multi-age groups to investigate properly moderating effects through SEM(path analysis) and difference test. Therefore, it is academical and practical worth that we developed our model to appropriate on mobile advertising's unique property and that we verified our hypotheses and variables focused on age group, whereas previous research did not. For this, we surveyed 345 samples for conducting structural equation modeling in empirical approach. The results of this study supported the statistical significance of all hypotheses except but convenience.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.361-366
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• 2019

In developing the avionics system, a system integration laboratory (SIL) is established to verify the function and interworking of individual components. In case of individual verification of SIL's components and system integration, a SIL model that simulates the function and interworking of each equipment is developed and used. A SIL model shall be pre-verified against all data defined in the interface control document (ICD) before interworking with the actual equipment and reverified even when the ICD changes or functions change. However, if the verification of the SIL model is performed manually, the verification of the individual SIL model takes considerable time. For this reason, selective regression tests are often performed to determine a impact of SIL models on ICD changes and some functional changes. In this paper, we designed SIL model verification automation method to perform regession test by reducing verification time of SIL model and verify the usefulness of verification automation design by developing SIL model verification automation tool.

• Journal of Ocean Engineering and Technology
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• v.33 no.5
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• pp.394-399
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• 2019

Plywood is a laminated wood material where alternating layers are perpendicular to each other. It is used in a liquefied natural gas (LNG) carrier for an insulation system because it has excellent durability, a light weight, and high stiffness. An LNG cargo containment system (LNG CCS) is subjected to loads from gravity, sloshing impact, hydrostatic pressure, and thermal expansion. Shear forces are applied to an LNG CCS locally by these loads. For these reasons, the materials in an LNG CCS must have good mechanical performance. This study evaluated the shear behavior of plywood. This evaluation was conducted from room temperature ($25^{\circ}C$) to cryogenic temperature ($-163^{\circ}C$), which is the actual operating environment of an LNG storage tank. Based on the plywood used in an LNG storage tank, a shear test was conducted on specimens with thicknesses of 9 mm and 12 mm. Analyses were performed on how the temperature and thickness of the plywood affected the shear strength. Regardless of the thickness, the strength increased as the temperature decreased. The 9 mm thick plywood had greater strength than the 12 mm thick specimen, and this tendency became clearer as the temperature decreased.

• Journal of Digital Convergence
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• v.19 no.11
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• pp.625-633
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• 2021

This study is aimed to verify the impact of health literacy on communication competence in nursing students. 104 nursing students participated in this descriptive research with an online self-reported questionnaire from May 3 to 21, 2021, at a university located in G city. The data were analyzed by two-sample t-test, ANOVA and hierarchical regression with SPSS program. The score of health literacy was 48.62/66 and the communication competence was 59.60/75. More than half perceived that the average reading level of Korean adults was higher than the actual. subjective health status(β=.309, p<.001), health literacy(β=.284, p=.002) and subjective academic grade(β=.235, p=.009) had significant influence on communication competence in the nursing students(F=10.546, p<.001). The explanatory power increased 7.3% more by adding health literacy(F=10.339, p=.002). To enhance communication competence of nursing students, more systematic curriculums to improve health literacy are needed.

• International Journal of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.157-167
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• 2023

As a new trend in the development of urban public spaces, the use of right-angle LED screens perfectly combines building facades with naked-eye 3D visual effects, providing designers with a brand-new creative platform. How to create a realistic naked-eye 3D effect on a right-angle LED screen and bring an immersive visual experience to the audience has become a question worth exploring. So far, production companies have yet to announce the relevant design ideas and complete production methods. In order to explore the production principle and production process of the naked-eye 3D effect of the right-angle LED screen, we summarize the basic production principle of the naked-eye 3D impact of the right-angle LED screen through case analysis. Based on understanding the production principle, the actual case production test was carried out, and a complete production process of the naked eye 3D visual effect of the right-angle led screen was tried to be provided by off-line rendering. For the problem of how to deal with image deformation, we provide two production methods: post-production software correction and UV mapping. Among them, the UV mapping method is more efficient and convenient. Referring to this paper can help designers quickly understand the production principle of the naked eye 3D effect of right-angle LED screens. The production process proposed in this paper can provide a reference for production method for related project producers.

• Journal of Korean Society of Water and Wastewater
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• v.37 no.6
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• pp.363-373
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• 2023

Numerous studies have established a correlation between sociodemographic characteristics and water usage, identifying population as a primary independent variable in mid- to long-term demand forecasting. Recent dramatic sociodemographic changes, including urban concentration-rural depopulation, low birth rates-aging population, and the rise in single-person households, are expected to impact water demand and supply patterns. This underscores the necessity for operational and managerial changes in existing water supply systems. While sociodemographic characteristics are regularly surveyed, the conducted surveys use aggregate units that do not align with the actual system. Consequently, many water demand forecasts have been conducted at the administrative district level without adequately considering the water supply system. This study presents an upward water demand forecasting model that accurately reflects real water facilities and consumers. The model comprises three key steps. Firstly, Statistics Korea's SGIS (Statistical Geological Information System) data was reorganized at the DMA level. Secondly, DMAs were classified using the SOM (Self-Organizing Map) algorithm to consider differences in water facilities and consumer characteristics. Lastly, water demand forecasting employed the PCR (Principal Component Regression) method to address multicollinearity and overfitting issues. The performance evaluation of this model was conducted for DMAs classified as rural areas due to the insufficient number of DMAs. The estimation results indicate that the correlation coefficients exceeded 0.9, and the MAPE remained within approximately 10% for the test dataset. This method is expected to be useful for reorganization plans, such as the expansion and contraction of existing facilities.

• Journal of Korean society of Dental Hygiene
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• v.24 no.1
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• pp.57-67
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• 2024

Objectives: This study aimed to assess the impact of care workers' knowledge of elderly oral health, education on elderly oral healthcare and behavioral needs, awareness of elderly oral healthcare, and actual practices in elderly oral healthcare. Furthermore, it explores the mediating effects of elderly oral healthcare education and behavioral needs on the relationship between awareness and practice. Methods: Data were collected from October 11 to December 29, 2023, from 172 certified care workers employed in nursing hospitals and other workplaces. For analyzing the data, t-test, one-way ANOVA, Pearson's correlation, and hierarchical regression were conducted using SPSS Statistics 21.0. Results: Elderly oral health knowledge, education and behavioral needs, awareness, and practice were significantly higher among: those aged 51 years and older, female, primarily working in nursing hospitals, with a total career span of 10 years, higher job satisfaction, in organizations prioritizing elderly oral healthcare, and with superior education in elderly oral health. Elderly oral healthcare education and behavioral needs had partial mediating effects on the relationship between care workers' awareness and practice of elderly oral healthcare. Conclusions: The current practices and challenges in care workers' oral healthcare for the elderly will be analyzed, and recommendations and strategies for improving practices will be formulated.