• Journal of Advanced Navigation Technology
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• v.23 no.1
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• pp.55-60
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• 2019

The web is one of the most intimate technologies in people's daily lives, and most of the time, people are sharing data on the web. Simple messenger, news, video, as well as various data are now spreading through the web. In addition, with the emergence of Web assembly technology, the programs that run in the existing native environment start to enter the domain of the Web, and the data shared by the Web is now getting wider and larger in terms of VR / AR contents and big data. Therefore, in this paper, we have studied how to effectively deliver web contentsto users who use Web service by using service worker that can operate independently without being dependent on browser and cache API that can effectively store data in web browser.

• Journal of Digital Convergence
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• v.17 no.4
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• pp.335-344
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• 2019

This study aimed to identify the effect of stress, smartphone addiction, Social support, and physiological index on quality of sleep (PSQI) and to investigate the affecting factors according to sex in highschool students. The data were collected from 210 subjects from February 6 to 16, 2018 using a structured self-report questionnaires and analyzed using descriptive statistics, t-test, ANOVA, and multiple regression with SPSS WIN Version 24.0. The quality of sleep was lower in female students than in male students. In multiple regression analysis, Awake time, School grades stress were significant predictors and explained 29.6% of quality of sleep for male students. In female students, Smart phone start age, School grades stress, Disability of daily living and Appraisal social support were significant predictors and explained 24.3% of quality of sleep. Therefore, it is expected to be used as basic data for the development of intervention programs that can solve the factors affecting the quality of sleep of adolescents, thereby helping the healthy development of youth.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.5
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• pp.799-806
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• 2021

In the IoT environment, event data from sensors is continuously reported over time. Event data obtained in this trend is accumulated indefinitely, so a method for efficient analysis and management of data is required. In this study, a data stream segmentation method was proposed to support the effective selection and utilization of event data from sensors that are continuously reported and received. An identifier for identifying the point at which to start the analysis process was selected. By introducing the role of these identifiers, it is possible to clarify what is being analyzed and to reduce data throughput. The identifier for stream segmentation proposed in this study is a semantic-oriented data stream segmentation method based on the event occurrence of each stream. The existence of identifiers in stream processing can be said to be useful in terms of providing efficiency and reducing its costs in a large-volume continuous data inflow environment.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.1
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• pp.83-94
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• 2018

UNESCO has continued to work in Africa, especially in the six southern sub-Saharan countries, and Asia, where international cooperation is needed. The CLC (Rwanda Community Learning Center) covered in this study aims to create a regional learning center in Rwanda and to recover local communities and provide learning environment. During the course of this study, we conducted field trips for actual planning and reviewed the current state of educational and cultural facilities that recently opened and are operated, and found implications. In consultation with the Rwandan Educational Commission, the site for CLC was decided, the building was designed, and the construction is about to start. The results of this study are as follows. First, in addition to the efforts of the activists in the village, which can be considered the smallest unit of a local community, the approach for establishing an architectural space and active education and community environment can be evaluated as a result of experimental efforts. Second, we can pay attention to the attempts to realize local communities. The bridge business is based on the multi-purposes such as early childhood education, technical education for adults, and community restoration of local residents and it reflects space and program plans for this purposes. It also reflects detailed plans such as differentiating the flow planning depending on users' time of use. Third, we can explain the characteristics of architectural planning considering local characteristics such as active use of local materials. Due to the characteristics of a developing country, there were significant considerations on maintenance, and to this end, the plan included plans for the environment and use of materials that are easily maintained. In addition, the participation of local residents in the process of establishment was suggested as a possibility to serve an educational role.

• Earthquakes and Structures
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• v.20 no.1
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• pp.1-12
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• 2021

The occurrence of progressive collapse induced by the removal of the vertical load-bearing element in the structure, because of fire or earthquake, has been a significant challenge between structural engineers. Progressive collapse is defined as the complete failure or failure of a part of the structure, initiating with a local rupture in a part of the building and can threaten the stability of the structure. In the current study, the behavior of the structures equipped with a cylindrical friction damper, when the vertical load-bearing elements are eliminated, is considered in two cases: 1-The load-bearing element is removed under the gravity load, and 2-The load-bearing element is removed due to the earthquake lateral forces. In order to obtain a generalized result in the seismic case, 22 pair motions presented in FEMA p 695 are applied to the structures. The study has been conducted using the vertical push down analysis for the case (1), and the nonlinear time-history analysis for the second case using OpenSEES software for 5,10, and 15-story steel frames. Results indicate that, in the first case, the load coefficient, and accordingly the strength of the structure equipped with cylindrical friction dampers are increased considerably. Furthermore, the results from the second case demonstrate that the displacements, and consequently the forces imposed to the structure in the buildings equipped with the cylindrical friction damper substantially was reduced. An optimum slip load is defined in the friction dampers, which permits the damper to start its frictional damping from this threshold load. Therefore, the optimum slip load of the damper is calculated and discussed for both cases.

• Food Science and Industry
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• v.49 no.4
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• pp.40-63
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• 2016

John Glenn, America's first man to eat anything in the near-weightless environment of Earth orbit, found the task of eating fairly easy. With improved packaging came improved food quality and menus. By the time of the Apollo Program, the quality and variety of food increased even further. Apollo astronauts were the first to have hot water, which made rehydrating foods easier and improved the food's taste. Thermostabilized pouches were also introduced on Apollo. The task of eating in space got a big boost in Skylab. It also had a food freezer and refrigerator a convenience offered by no other vehicle before or since. Two different food systems will be used for future long-duration missions to other planets, one for traveling to and from the distant body and one for use on the surface of the moon or Mars. The transit food system will be similar to the space station food system with the exception that products with three-to five-year shelf lives will be needed. Thus, this part of the trip will be similar to what occurs aboard space missions now. The surface food system, be it lunar or planetary, will be quite different. It will be similar to a vegetarian diet that someone could cook on Earth. Once crew members arrive on the surface and establish living quarters, they can start growing crops. Once the crops are processed into edible ingredients, cooking will be done in the spacecraft's galley to make the food items. Disposal of used food packaging will be an issue since there will be no Progress vehicles to send off and incinerate into the Earth's atmosphere. Packaging materials will be used that have less mass but sufficient barrier properties for oxygen and water to maintain shelf life as those now in use.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.49-56
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• 2004

An Internet draft, named RR(Return Routability) protocol, proposed to IETF mobileip WG, in order to establish an optimal path to MN(Mobile Node) by securely sending the BU(Binding Update) message to CN(Correspondent Node). However, it has some problems with initiating the protocol by the MN: it causes to increases in communication load in the home network, to increases communication delay between MN and CN, and increases in communication load due to unnecessary message exchanges. To resolve the problems, this paper proposes an alternative scheme for the RR protocol in MIPv6. The proposed scheme is devised to start the protocol by HA on receiving the first packet from CN. It decreases the route optimization overhead by reducing the number of BU messages as well as the communication time. Beside these advantages, this scheme provides the same security grade as the original RR protocol.

• Journal of Korean Society for Quality Management
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• v.49 no.1
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• pp.81-95
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• 2021

Purpose: The purpose of this study was to analysis pattern of nonconforming farmers who is one of the factors of unconformity in residual pesticides. Methods: Pattern analysis of nonconforming farmers were analyzed through convergence of safety data and farmer's DB data. Exploratory data analysis and association rule analysis were used for extracting factors related to unconformity. Results: The results of this study are as follows; regarding the exploratory data analysis, it was found that factors of farmers influencing unconformity in residual pesticides by total 9 factors; sampling time, gender, age, cultivation region, farming career, agricultural start form, type of agriculture, cultivation area, classification of agricultural products. Regarding the association rule analysis, non-conformity association rules were found over the past three years. There was a difference in the pattern of nonconforming farmers depending on the cultivation period. Conclusion: Exploratory data analysis and association rule analysis will be useful tools to establish more efficient and economical safety management plan for agricultural products.

• Journal of Aerospace System Engineering
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• v.16 no.3
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• pp.35-41
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• 2022

UAM (Urban Air Mobility) is a new safe, secure, and more sustainable air transportation system for passengers and cargo in urban environments. Commercial operations of UAM are expected to start in 2025. Since production rates of UAM are expected to be closer to cars than conventional aircraft, the airworthiness methodology for UAM must be prepared for mass production. Composite materials are expected to be mainly used for UAM structures to reduce weight. In this paper, the composite material qualification method was derived and the materials were applied for small aircraft application. It is expected to reduce the airworthiness certification time by applying composite material qualification system and its database.

• Women's Health Nursing
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• v.28 no.3
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• pp.222-234
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• 2022

Purpose: This study investigated the changes in the health-related behaviors of adult women in Korea during the coronavirus disease 2019 (COVID-19) pandemic. Methods: Data from the eighth Korea National Health and Nutrition Examination Survey (2019-2020) were analyzed. The participants were 4,848 women aged 19 to 64 years in 2019 and 2020. Data analysis using the complex sampling design was performed using SPSS 20.1. Results: Positive changes during the pandemic compared to before the pandemic in Korean adult women were found for improved subjective oral health perceptions (odds ratio [OR], 1.77; p<.001), increased moderate-intensity exercise in work and leisure activities (OR, 1.75; p<.001 and OR; 1.29, p=.004), and a decrease in secondhand smoke exposure at the workplace and in public places (OR, 0.64; p=.004 and OR, 0.60; p<.001). However, the following negative health behavior changes were found: decreased frequency of walking 5 days a week (OR, 0.81; p=.011) and an increase in unhealthy daytime sleep durations (OR, 1.40; p=006). Conclusion: Compared to before the COVID-19 pandemic, Korean adult women perceived their subjective dental health more positively during the COVID-19 pandemic, decreased their exposure to secondhand smoke at work and in public places, decreased walking, and increased sleep duration during the week. Since this study only compared data between 1 year before and after the start of the pandemic, it is necessary to investigate a longer period of time in the future. A future study should attempt to identify the factors related to changes in health behaviors caused by the pandemic.