• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.5
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• pp.134-142
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• 2011

Although combustion is essential in most energy generation processes, it is one of the major causes of air pollution. Exhaust pipes with circular fin were designed to study the effect of cooling the recirculated exhaust gases (EGR) of Diesel engines on the chemical composition of the exhaust gases and the reduction in the percentages of pollutant emissions. The gases examined in this study were oxides of nitrogen (NOx), carbon dioxide ($CO_2$) and carbon monoxide (CO). In addition, $O_2$ concentration in the exhaust was measured. The designs adopted in this study were about exhaust pipes with solid and hollow fins around them direct surface force measurement in water using a nano size colloidal probe technique. The direct force measurement between colloidal surfaces has been an essential topic in both theories and applications of surface chemistry. As particle size is decreased from micron size down to true Carbon nano Colloid size (<10 nm), surface forces are increasingly important. Nano particles at close proximity or high solids loading are expected to show a different behavior than what can be estimated from continuum and mean field theories. The current tools for directly measuring interaction forces such as a surface force apparatus or atomic force microscopy (AFM) are limited to particles much larger than nano size. This paper use Water and CNC fluid at normal cooling system of EGR. Experimental result showed all good agreement at Re=$2.54{\times}10^4$ by free convection and Re=$3.36{\times}10^4$ by forced air furnace.

• Communications of Mathematical Education
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• v.24 no.3
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• pp.611-626
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• 2010

The purpose of this study is to explore the composite properties of linear functions using CAS calculators. The meaning and processes in which technological tools such as CAS calculators generated to instrument are reviewed. Other theoretical topic is the design of an exploring model of observing-conjecturing-reasoning and proving using CAS on experimental mathematics. Based on these background, the researchers analyzed the properties of the family of composite functions of linear functions. From analysis, instrumental capacity of CAS such as graphing, table generation and symbolic manipulation is a meaningful tool for this exploration. The result of this study identified that CAS as a mediator of mathematical activity takes part of major role of changing new ways of teaching and learning school mathematics.

• Journal of Korea Society of Digital Industry and Information Management
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• v.17 no.2
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• pp.85-101
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• 2021

This study aims to gain insight through understanding the Metaverse, which has recently become a hot topic. The study utilizes the methods of case study and News Bigdata Analysis Services. The Metaverse can be defined as a world with no separation between the virtual and real worlds. Currently, the Metaverse is dominated mainly by the MZ generation, but just like smartphones have quickly entered our lives, the Metaverse will soon, too, become a part of our lives. To follow up on this change, all companies, including global companies, are going after the Metaverse. Today, the Metaverse is successfully being used in all types of fields, including gaming, performing arts, business, etc., and its essential technologies include VR/AR/MR/XR and AI. This study intends to help understand the Metaverse through a case analysis of Zepeto, which has 200 million users worldwide. On Zepeto, users can decorate their own avatars, hang out with friends, go to art galleries and performances, and create and sell items. Of these users, 90% are from outside of South Korea, and 80% are teenagers. With most of the users being underage, many legal and social problems also follow. Nevertheless, who will be the first to conquer the new world of the Metaverse will continue to be a big issue. This study also analyzes domestic news articles about the Metaverse by utilizing the BigKinds system. Starting in 1996, the number of articles about the Metaverse each year remains single digit, until in 2020 when the number sharply rises to 86 news. As of June 2021, there are 1,663 articles on the Metaverse. This study suggests that the Metaverse should now be carefully examined and closely followed.

• Journal of Korean Society on Water Environment
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• v.38 no.5
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• pp.240-246
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• 2022

Water and energy are inextricably linked and referred to as 'Water-Energy Nexus'. Recently, this topic has been drawing a lot of attention from various studies due to the exacerbated water availability. Korea's water and energy consumption has been increasing consistently, which calls for better management. This paper aims to identify changes in electricity consumption in relation to water intake and purification processes. Using Log Mean Divisia Index (LMDI) Decomposition Analysis method, this study attributes the changes to major factors such as; Total population (population effect), household/population (structure effect), GDP/household (economic effect), and water-related energy use/GDP (unit effect). The population effect, structure effect, and economic effect contributed to an increase in water-related electricity consumption, while the unit effect contributed to a decrease. As of 2019, the economic effect increased the water supply sector's electricity consumption by 534 GWh, the population effect increased by 73 GWh, and the structure effect increased by 243 GWh. In contrast, the unit effect decreased the electricity consumption by -461 GWh. We would like to make the following suggestions based on the findings of this study; first, the unit effect must be improved by increasing the energy efficiency of water intake and purification plants and installing renewable energy power generation facilities. Second, the structure effect is expected to increase over time, and to mitigate it, water consumption must be reduced through water conservation policies and the improvement of water facilities. Finally, the findings of this study are expected to be used as foundational data for integrated water and energy management.

• Journal of Broadcast Engineering
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• v.27 no.5
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• pp.619-628
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• 2022

Although face recognition and face generation have been growing in popularity, the privacy issues of using facial images in the wild have been a concurrent topic. In this paper, we propose a face editing network that can reduce privacy issues by generating face images with various properties from a small number of real face images and facial mask information. Unlike the existing methods of learning face attributes using a lot of real face images, the proposed method generates new facial images using a facial segmentation mask and texture images from five parts as styles. The images are then trained with our network to learn the styles and locations of each reference image. Once the proposed framework is trained, we can generate various face images using only a small number of real face images and segmentation information. In our extensive experiments, we show that the proposed method can not only generate new faces, but also localize facial attribute editing, despite using very few real face images.

• Journal of the Korea Society of Computer and Information
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• v.27 no.12
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• pp.209-217
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• 2022

Naval CMS(Combat Management System) is linked to various sensors and weapon equipment and use DDS(Data Distribution Service) for efficient data communication between ICU(Interface Control Unit) Node and IPN(Information Processing Node). In order to use DDS, software in the system communicates in an PUB/SUB(Publication/Subscribe) based on DDS topic. If the DDS messages structure in this PUB/SUB method does not match, problems such as incorrect command processing and wrong information delivery occur in sending and receiving application software. To improve this, this paper proposes a DDS message structure integrity verification method. To improve this, this paper proposes a DDS message structure integrity verification method using a hash tree. To verify the applicability of the proposed method to Naval CMS, the message integrity verification rate of the proposed method was measured, and the integrity verification method was applied to CMS and the initialization time of the existing combat management system was compared and the hash tree generation time of the message structures was measured to understand the effect on the operation and development process of CMS. Through this test, It was confirmed that the message structure verification method for system stability proposed in this paper can be applied to the Naval CMS.

• Human Ecology Research
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• v.60 no.4
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• pp.625-643
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• 2022

The purpose of this study was to explore the trends and core keywords of the secondary school home economics teacher selection test using content analysis and text network analysis. The sample comprised texts of the secondary school home economics teacher 1st selection test for the 2017-2022 school years. Determination of frequency of occurrence, generation of word clouds, centrality analysis, and topic modeling were performed using NetMiner 4.4. The key results were as follows. First, content analysis revealed that the number of questions and scores for each subject (field) has remained constant since 2020, unlike before 2020. In terms of subjects, most questions focused on 'theory of home economics education', and among the evaluation content elements, the highest percentage of questions asked was for 'home economics teaching·learning methods and practice'. Second, the network of the secondary school home economics teacher selection test covering the 2017-2022 school years has an extremely weak density. For the 2017-2019 school years, 'learning', 'evaluation', 'instruction', and 'method' appeared as important keywords, and 7 topics were extracted. For the 2020-2022 school years, 'evaluation', 'class', 'learning', 'cycle', and 'model' were influential keywords, and five topics were extracted. This study is meaningful in that it attempted a new research method combining content analysis and text network analysis and prepared basic data for the revision of the evaluation area and evaluation content elements of the secondary school home economics teacher selection test.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.427-429
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• 2022

Recently, metaverse technology is being used in various service industries such as games, entertainment, manufacturing, distribution, advertising, and education. Studies on the correlation between the continuous use of devices used in metaverse content are still insufficient. In order to be more immersed in the metaverse, it is necessary to develop a natural movement and an easy-to-use input device. Based on flow, this study was conducted on the topic of continuous use of metaverse contents and devices. The constituent factors of Flow, an independent variable, were set as sense of reality, immersion, and interaction. We intend to use the data of 500 male and female metaverse users for research through a survey institution. Among the flow factors that increase the continuous use of metaverse contents and devices, the factors that have the greatest influence were studied. Through the results of this study, it is intended to help establish the direction of the next-generation metaverse content and device industry.

• Tuberculosis and Respiratory Diseases
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• v.86 no.2
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• pp.120-132
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• 2023

Background: To systematically review studies on inhaled corticosteroids (ICS) and lung cancer incidence in chronic airway disease patients. Methods: We conducted electronic bibliographic searches on OVID-MEDLINE, EMBASE, and the Cochrane Database before May 2020 to identify relevant studies. Detailed data on the study population, exposure, and outcome domains were reviewed. Results: Of 4,058 screened publications, 13 eligible studies in adults with chronic obstructive pulmonary disease (COPD) or asthma evaluated lung cancer incidence after ICS exposure. Pooled hazard ratio and odds ratio for developing lung cancer in ICS exposure were 0.81 (95% confidence interval, 0.64 to 1.02; I²=95.7%) from 10 studies and 1.02 (95% confidence interval 0.50 to 2.07; I²=94.7%) from three studies. Meta-regression failed to explain the substantial heterogeneity of pooled estimates. COPD and asthma were variously defined without spirometry in 11 studies. Regarding exposure assessment, three and 10 studies regarded ICS exposure as a time-dependent and fixed variable, respectively. Some studies assessed ICS use for the entire study period, whereas others assessed ICS use for 6 months to 2 years within or before study entry. Smoking was adjusted in four studies, and only four studies introduced 1 to 2 latency years in their main or subgroup analysis. Conclusion: Studies published to date on ICS and lung cancer incidence had heterogeneous study populations, exposures, and outcome assessments, limiting the generation of a pooled conclusion. The beneficial effect of ICS on lung cancer incidence has not yet been established, and understanding the heterogeneities will help future researchers to establish robust evidence on ICS and lung cancer incidence.

• 한국노년학
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• v.32 no.2
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• pp.541-557
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• 2012

This study aims to understand public perceptions of aging Korean society and related factors in the context of population aging and generational difference. Data are from 1,498 individuals older than 20 who were recruited through the quota sampling technique. Results indicated that the respondents reported less then three as the number of positive aspects of aging Korean society. Among the factors related to population aging, such as knowledge about aging, perceptions about family care, anxiety about later life, and perspectives about generational conflict, anxiety about later life was shown to be negatively associated with perception of aging Korean society across age groups. Respondents 65 and older showed more positive perception about aging Korean society and this association was conditioned by perspectives about generational conflict. Perspectives about generational conflict revealed positive associations with perception of aging Korean society among respondents aged 20-44 and 45-64, while no association was found among those 65 and older. Discussions focused on ways to alter perceptions of aging Korean society and needs for future research on this topic.