• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.2
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• pp.129-140
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• 2018

A residual stress generated in the steel structure is broadly categorized into initial residual stress during manufacturing steel material, welding residual stress caused by welding, and heat treatment residual stress by heat treatment. Initial residual stresses induced during the manufacturing process is combined with welding residual stress or heat treatment residual stress, and remained as a final residual stress. Because such final residual stress affects the safety and strength of the structure, it is of utmost importance to measure or predict the magnitude of residual stress, and to apply this point on the design of the structure. In this study, the initial residual stress of steel structures having thicknesses of 25 mm and 70 mm during manufacturing was measured in order to investigate initial residual stress (hereinafter, referred to as initial stress). In addition, thermal elastic plastic FEM analysis was performed with this initial condition, and the effect of initial stress on the welding residual stress was investigated. Further, the reliability of the FE analysis result, considering the initial stress and welding residual stress for the steel structures having two thicknesses, was validated by comparing it with the measured results. In the vicinity of the weld joint, the initial stress is released and finally controlled by the weld residual stress. On the other hand, the farther away from the weld joint, the greater the influence of the initial stress. The range in which the initial stress affects the weld residual stress was not changed by the initial stress. However, in the region where the initial stress occurs in the compressive stress, the magnitude of the weld residual compressive stress varies with the compression or tension of the initial stress. The effect of initial stress on the maximum compression residual stress was far larger when initial stress was considered in case of a thickness of 25 mm with a value of 180 MPa, while in case of thickness at 70 mm, it was 200 MPa. The increase in compressive residual stress is almost the same as the initial stress. However, if initial stress was tensile, there was no significant change in the maximum compression residual stress.

• Journal of Navigation and Port Research
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• v.45 no.4
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• pp.224-230
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• 2021

It has been 16 years since the government announced its first Ocean Education Policy in 2005. Although the public consensus on the importance of ocean education has been formed, it is impossible to objectively analyze the impact of the policy on the society or the economy. The aim of this paper was to identify differences in perceptions and behaviors about the ocean between groups participating in ocean education and non-participating groups and to analyze the effectiveness of ocean education by developing measurement indicators for the value that individuals gave to ocean education services. To conduct this study, first, the value of ocean education was defined and value items that could be provided to individuals were classified. Second, to develop indicators that could measure classified value items, a Delphi survey was conducted to collect opinions of various experts. Third, by measuring the content validity ratio (CVR) for each item, final indicators and questionnaire were derived. As a result of Delphi analysis, 18 items with a CVR value of 0.6 or higher were finally adopted out of 32 indicator items. In the cognitive value category, indicators that could identify an individual's level of knowledge of the ocean, change in perception, and problem-solving ability were selected. In the behavioral value category, indicators were expanded to judge changes in attitudes and relationships toward the ocean and responsible behavior in more detail. This study is meaningful in that it provides the basis for directly judging the value of ocean education service provided by the government to the people. Results of such analysis are expected to contribute to securing a stable budget and the justification for expanding human resources in the government's continuous promotion of ocean education policies.

• Journal of Digital Convergence
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• v.19 no.9
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• pp.33-42
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• 2021

Despite the importance of science education in an informal environment, the reality is that there is a lack of trend analysis research on 'Informal Science Learning (ISL)' and its effects. Therefore, the purpose of this paper is to find out the educational effects of ISL and how to use it, and to provide guidelines for future ISL research directions. This study classifies specific ISL-related papers published from 2010 to 2019 and compares them with each element of GLO used to measure the effectiveness of informal education. The fit of the analyzed data was checked for each part through SPSS and Chi-Square. In conclusion, it was found that researchers are using 'ISL' to pursue 'Knowledge and Understanding' and 'Attitudes and Values' among the five performance indicators of 'GLO'. On the other hand, 'Skills' and 'Enjoyment, Inspiration and Creativity' appear to have the least expectations, so supplementation is required in these areas in the future. In addition, this study intends to suggest a direction for informal science education-related program development and future research to various education workers.

• Journal of Internet Computing and Services
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• v.22 no.2
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• pp.59-68
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• 2021

As artificial intelligence(AI) technologies, which have made rapid growth recently, began to be applied to the marine environment such as ships, there have been active researches on the application of CNN-based models specialized for digital videos. In E-Navigation service, which is combined with various technologies to detect floating objects of clash risk to reduce human errors and prevent fires inside ships, real-time processing is of huge importance. More functions added, however, mean a need for high-performance processes, which raises prices and poses a cost burden on shipowners. This study thus set out to propose a method capable of processing information at a high rate while maintaining the accuracy by applying Quantization techniques of a deep learning model. First, videos were pre-processed fit for the detection of floating matters in the sea to ensure the efficient transmission of video data to the deep learning entry. Secondly, the quantization technique, one of lightweight techniques for a deep learning model, was applied to reduce the usage rate of memory and increase the processing speed. Finally, the proposed deep learning model to which video pre-processing and quantization were applied was applied to various embedded boards to measure its accuracy and processing speed and test its performance. The proposed method was able to reduce the usage of memory capacity four times and improve the processing speed about four to five times while maintaining the old accuracy of recognition.

• International Area Studies Review
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• v.13 no.3
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• pp.191-210
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• 2009

Energy Security has been factor of great importance to national security, economy, society and all other areas. However, it has been in the lack of situation where there is no leading method to measure energy security nor to compare among countries until now. In the research, objective index to assess energy security has been developed and compared among the level of countries in terms of energy importing countries' perspective. Based on the suggested index, comparison for the energy security level has been explained. The implication of the research is that in terms of energy importing perspectives, method to appraise energy security and according to this, energy security rate by each countries with respect to LNG. This method is doubtlessly applicable to comparison of security rate from other resources and fluctuation of energy security by reflecting other factors. Also, discussion about how increased autonomy of resources can impact Korean energy security with regard to recent international energy development. As a consequence, it has revealed that enhanced authority of resources evokes ascendancy of energy security in a positive way.

• Nutrition Research and Practice
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• v.13 no.4
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• pp.352-357
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• 2019

BACKGROUND/OBJECTIVES: Youth is the crucial stage between childhood and adulthood during which an individual acquires new behavior and practices including dietary habits, that may be influenced by his peers, social circle, nutrition knowledge level and other factors. The increase in awareness of young adults is of special importance from the perspective of health and prevention of obesity related chronic diseases. To measure the nutrition literacy level of university students using the Turkish version of Adolescent Nutrition Literacy Scale (ANLS). We evaluated their food habits using the Adolescent Food Habit Checklist (AFHC) tool and analysed it, if the eating habits were affected by nutrition literacy level. SUBJECTS/METHODS: A cross-sectional descriptive study was conducted on randomly selected 276 students studying in the Faculty of Health Sciences of Istanbul Aydin University, Turkey. Data was collected by means of ANLS and AFHC tools by face to face interview method. SPSS statistical sofware (IBM SPSS Statistics 19) was used to analyse the obtained data. RESULTS: Participants comprised of 47.1% males and 52.9% females with mean age of $20.0{\pm}1.60years$. Mean body mass index (BMI) was determined as $22.4{\pm}3.76$ ($23.6{\pm}3.63$ males $21.3{\pm}3.57$ females). Functional, interactive and critical nutritional literacy scores for male participants were $22.49{\pm}5.71$, $17.45{\pm}4.84$, and $28.28{\pm}7.13$ respectively (total $64.98{\pm}10.15$). For females the values were $24.66{\pm}5.13$, $20.17{\pm}4.28$, and $32.20{\pm}5.65$ (total $69.72{\pm}8.59$) respectively. For all the three sub-categories of nutrition literacy, the scores acquired by females were significantly higher than males (P < 0.001). In the AFHC tool, the mean score acquired by males were $9.26{\pm}4.18$ whereas for females it was $10.37{\pm}3.40$ significantly higher as compared to males (P = 0.007). CONCLUSION: The food habits of female participants were better than males; in accordance with their nutrition literacy status. It may be concluded that food habits are influenced by nutrition literacy and therefore stress much be given to increase the nutrition awareness among children youth as well as adults.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.508-515
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• 2018

The purpose of this study was to analyze the errors of the built - in dose area product and the calibrated moving dose area product when using automatic exposure controller of the interventional equipment. And then, the importance of the dosimeter calibration and the necessity of the calibration guideline were investigated. The experimental method was to assemble the phantom into Thin, Normal, and Heavy Adult according to the NEMA Phantom manual and to measure the dose area with the built-in dose area product and the moving dose area product. As a result, in all thicknesses, the built-in dose area product showed higher doses than the moving dose area product, and the thicker the thickness, the larger the difference. In addition, paired t-test was performed for each item and there was a significant difference in each item between p<0.05. In conclusion, considering the intervention which is highly exposed to the radiation exposure, it is that we have to know the accurate dose when using the AEC of the equipment. And there is no calibration guide for the built-in dose area meter, thus calibration guidelines should be prepared.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.291-297
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• 2019

The world's leading industrialized nations are improving their national science and technology capacity through the continuous expansion of national R&D investment and the improvement of performance in accordance with the trend of the fourth industrial revolution. As rapid technological development following technological convergence necessitates a preemptive response to a new paradigm, the importance of securing high technology that affects the national competitiveness is increasing day by day. Core technologies and future new technologies that affect national competitiveness can be seen as a measure to upgrade the nation's innovative capabilities. In particular, the core technologies and future new technologies to prepare for changes in a security environment and future battlefields are very important in the defense sector that develops weapons systems. In the defense sector, the core technologies based on the military weapons systems are identified, and future new technologies that use the best technologies of the private sector for national defense, not on the needs of develops weapons systems, are derived. This study examined the characteristics of core technology and future new technology of defense ground unmanned systems, conducted a comparative study through empirical analysis, and concluded that strategic technology planning and research and development are needed according to the core technology and future new technology characteristics.

• Journal of agriculture & life science
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• v.52 no.6
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• pp.139-153
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• 2018

This study analyzes the economic effect of rehabilitation and upgrading of reservoirs as a prevented method against natural disasters under recent abnormal weather conditions and dam-break. For the analysis, we divide the purpose of rehabilitation and upgrading of reservoirs into the stable supply of rural water under uncertain weather conditions and the prevention of collapse due to the aging of the reservoir. We measure the economic effect of rehabilitation and upgrading of reservoirs by estimating the resident's willingness-to-pay for the project through Contingent Valuation Method(CVM). The result shows that distributions of willingness-to-pay to prevent natural disasters and dam-break are similar to each other. About 66% of the residents in sample regions are willing to pay for the project. The resident's willingness-to-pay to protect natural disasters and dam-break are 32,250 to 46,147 won and 28,427 to 47,308 won respectively on average for all sample regions. The comparison of willingness-to-pay by type of regions shows that paddy field areas are the highest followed by facility cultivation areas and urban areas. In addition, total expected value of the projects calculated based on the resident's willingness-to-pay for paddy field areas and facility cultivation areas are much larger than actual project costs. This implies that rural residents are fully aware of the importance of the project to prevent natural disasters and dam-break and are willing to pay for additional costs if needed.

• Korean Journal of Heritage: History & Science
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• v.46 no.3
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• pp.78-93
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• 2013

The purpose of this study is to analyze college students' perception of national natural heritages, including natural monumentsand scenic sites, in comparison with the similar concepts of national parks and eco-landscape preservation areas, to suggest managerial implications to enhance competitiveness. The first objective of this study is to measure their attitude toward traveling each type of natural heritage and to rate the relative importance of the four types of heritages in terms of preservation. Natural monuments were perceived as the most strongly preserved type, while scenic sites were perceived as the least strongly preserved type. The second objective is to conduct a correspondence analysis to match the concepts of four types of natural heritages with 10 tourist attractions representing the types. It was found that college students have difficulty appropriately identifying the types of 10 tourist attractions. In addition, multi-dimensional scaling (MDS) was implemented to identify the similarities and differences of the four types of natural heritages and to produce a positioning map matching the four types of natural heritages with the six attributes representing each type as a tourist attraction. Natural monuments were perceived very differently from scenic sites and not very differently from eco-landscape preservation areas. There were a few associations between the four types of natural heritages and the six tourism attributes, implying that little effort is made to promote and position each type of natural heritage in terms of tourism. In conclusion, a public awareness program is required to enhance the brand image of natural monuments and scenic sites in comparison to national parks and eco-landscape preservation areas. In addition, local residents who live near the natural heritages should be bolstered to play a managerial role as supporters and contents providers for sustainability.