• KIPS Transactions on Software and Data Engineering
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• v.10 no.10
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• pp.421-428
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• 2021

The High Efficiency Image File Format (HEIF) is an MPEG-developed image format that utilizes the video codec H.265 to store still screens in a single image format. The iPhone has been using HEIF since 2017, and Android devices such as the Galaxy S10 have also supported the format since 2019. The format can provide images with good compression rates, but it has a complex internal structure and lacks significant compatibility between devices and software, making it not popular to replace commonly used JPEG (or JPG) files. However, despite the fact that many devices are already using HEIF, digital forensics research regarding it is lacking. This means that we can be exposed to the risk of missing potential evidence due to insufficient understanding of the information contained inside the file during digital forensics investigations. Therefore, in this paper, we analyze the HEIF formatted photo file taken on the iPhone and the motion photo file taken on the Galaxy to find out the information and features contained inside the file. We also investigate whether or not the software we tested support HEIF and present the requirement of forensic tools to analyze HEIF.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.10
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• pp.391-398
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• 2021

Since the leased line is a structure that exclusively uses two connected areas for data transmission, a stable quality level and security are ensured, and despite the rapid increase in the number of switched lines, it is a line method that is continuously used a lot in companies. However, because the cost is relatively high, one of the important roles of the network operator in the enterprise is to maintain the optimal state by properly arranging and utilizing the resources of the network leased line. In other words, in order to properly support business service requirements, it is essential to properly manage bandwidth resources of leased lines from the viewpoint of data transmission, and properly predicting and managing leased line usage becomes a key factor. Therefore, in this study, various prediction models were applied and performance was evaluated based on the actual usage rate data of leased lines used in corporate networks. In general, the performance of each prediction was measured and compared by applying the smoothing model and ARIMA model, which are widely used as statistical methods, and the representative models of deep learning based on artificial neural networks, which are being studied a lot these days. In addition, based on the experimental results, we proposed the items to be considered in order for each model to achieve good performance for prediction from the viewpoint of effective operation of leased line resources.

• Journal of Family Resource Management and Policy Review
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• v.25 no.1
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• pp.47-61
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• 2021

The purpose of this study is to analyze the trend of changes in household labor among middle-aged generations who are facing dynamic changes in the middle of their life cycle. The research method is a literature study that examines and analyzes related data. Specifically, it aims to analyze the basic characteristics of middle-aged generations and trends in household labor, which are revealed through Time Use Survey, market trend reports, newspaper articles, and books. From the perspective of family resource management, housework is an unpaid activity performed by and for family members, and is an activity that can be replaced by purchasing goods or services from the market. This study focuses on the rapid growth of the home appliance market that replaces housework with the development of technology after industrialization, and how the change of technology affected the efficiency of housework. In addition, the composition and characteristics of middle-aged generations greatly changed according to changes in family structure, form, and family value. Examining the current state of housework and changing trends of middle-aged generations, which have different characteristics from previous generations, is significant in that it can predict future market trends and suggest implications for family policies that support the improvement of the quality of life of middle-aged generations.

• Journal of Climate Change Research
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• v.9 no.4
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• pp.303-312
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• 2018

In Ethiopia, climate change and deforestation are major issues hindering sustainable development. Local Ethiopian communities commonly perceive an increase in temperature and a decrease in rainfall. Meteorological data shows that rainfall has declined in southern Ethiopia, and spring droughts have occurred more frequently during the last 10-15 years. The frequently occurring droughts have seriously affected the agriculture-dominated Ethiopian economy. Forests can play an important role in coping with climate change. However, deforestation is alarmingly high in Ethiopia, and this is attributed mainly to agricultural expansion and fuel wood extraction. Deforestation has led to a decrease in various benefits from forest ecosystem services, and increased ecological and environmental problems including loss of biodiversity. To resolve the issues effectively, it is crucial to enhance climate change resilience through reforestation and various international collaborations are urgently needed. To continue collaboration activities for resolving these issues, it is first necessary to address fundamental questions on the nature of collaboration: does collaboration aim for a support-benefit or a mutual benefit situation; dividing the workload or sharing the workload; an advanced technology or an appropriate technology; and short-term and intensive or long-term and extensive?. Potential collaboration activities were identified by sectors: in the governmental sector, advancing governmental structure and policy, enhancing international collaborations and negotiations, and capacity building for forest restoration and management; in the research and education sector, identifying and filling gaps in forestry and climate change education, capacity building for reforestation and climate change resilience research, and developing bioenergy and feed stocks; and in the business and industry sector, supporting conservation based forestry businesses and industries, while promoting collaboration with the research and education sectors. It is envisaged that international collaboration for enhancing climate change resilience through reforestation will provide a strong platform for resolving climate change and deforestation issues, and achieving sustainable development in Ethiopia.

• 교육공학연구
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• v.33 no.4
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• pp.1001-1024
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• 2017

Flipped classroom has used widely in university in that its unique structure can facilitate learners' higher-thinking skills and promote competencies. Learners are expected to extend knowledge through performing online and offline, but they have difficulty in understanding their roles and specific behaviors to achieve the learning goals in the flipped learning. Therefore, a guidance for students has been required to support learners' mastery learning. The purpose of this study is to identify successful learners' characteristics in terms of "competency". For this, three-phased competency modeling was employed. In Phase I, Behavioral Event Interviews were conducted with eight learners of the flipped classroom. In Phase II for identifying competencies and developing a competency model, the data was coded, followed by testing reliability of the coding. Based on the meaning codes, competencies and behavioral indexes were developed. The final competencies consist of learning orientation, learning management, feedback seeking, peer interaction, and knowledge extension. In Phase III, validation of the competency model was conducted by explanatory factor analysis. As last, competencies were aligned by the two-phase of the flipped classroom. The finding will be used as the guidance for the learners and instructors in the flipped classroom.

• Membrane Journal
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• v.29 no.2
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• pp.111-121
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• 2019

An organic citrate series draw solute was synthesized using diethyl malonate for forward osmosis. The structure of the final compound potassium pentane-1,3,3,5-tetracarboxylate was confirmed by $^1H-NMR$ and $^{13}C-NMR$ analysis. Osmotic pressure, solubility, water permeability and reverse salt flux were measured for the properties of the draw solute. Forward osmosis results showed that the draw solute exhibited higher water flux than other draw solutes of trisodium citrate and tripotassium citrate. Reverse salt flux of all the organic daw solutes was much lower than that of NaCl. The osmotic pressure of the synthesized draw solute was 25% lower than that of NaCl. The solubility of the draw solute was 317 g/ 100 g water, which is 8.8 times higher than that of NaCl. A commercialized nanofiltration membrane was used for the recovery of the draw solute. The draw solute could be effectively recovered at low pressure.

• The Journal of the Korea Contents Association
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• v.19 no.8
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• pp.525-534
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• 2019

Korea is facing one of the fastest aging population problems in the world due to the extension of life expectancy and low birth rates due to economic development and the development of health care. It has become difficult to take care of elderly people in need of long-term care at home, and social problems such as dementia and the increase in stroke cases are serious problems. The government is enacting and implementing the Long-Term Care Insurance Act for the purpose of improving the quality of life for senior citizens subject to long-term care and alleviating the burden of family support in order to solve such social structure and problems for senior citizens. However, as a result of the implementation of the long-term care insurance system for the elderly, the privatization of the facilities and the disorder are causing widespread requests for public accountability of the services and the enhancement of the quality of the facilities. In addition, various arrangements are needed for the production of low-wage medical care workers, tasks for quality improvement, problems regarding financing methods, and so on. In order to maintain and develop the long-term care insurance system for the elderly, the government will consider seeking ways to improve the legal and institutional aspects according to changes in the social environment of the age, as well as seeking mental and psychological measures for the stabilization of old life as well as physical health.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.610-617
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• 2019

The urban-rural complex area in Korea has a distinctive spatial structure where the urban area and rural area coexist. Therefore, in order to cope with the over-depopulation in the rural region of the urban-rural complex area, it is necessary to explore various policies that can prevent the existing residents from leaving, and in fact support them to remain where they currently reside. In this context, this current study analyzed the factors affecting the existing residents' continuous intention to remain by employing the '2017 Chuncheon City Social Survey' as a countermeasure for the over-depopulation of the rural region in the urban-rural complex area. Especially, since a regional identity is determined endogenously, this study used a simultaneous bivariate ordered probit model with giving consideration to the endogenous relationship between a regional identity and a regional residents' intentions. As a result, it was found on analysis that the regional residential intention was higher as the regional identity was stronger. Furthermore, the regional identity was stronger as a householders' age and residence period were longer, and also as the residents were satisfied with their work leisure and life residence balance. It was also found that the residents' intention was higher as the residents' satisfaction with the local medical service and their work was increased. Thus, supporting policy is needed that can provide appropriate quality-of-life services in a timely manner, but only after identifying the demand for these services by the rural residents in the urban-rural complex area.

• Journal of Korean Dental Science
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• v.12 no.1
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• pp.13-19
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• 2019

Purpose: The aim of this study was to compare the flexural strength of provisional fixed dental prostheses which was three-dimensional (3D) printed by several build directions. Materials and Methods: A metal jig with two abutment teeth and pontic space in the middle was fabricated. This jig was scanned with a desktop scanner and provisional restoration was designed on dental computer-aided design program. On the preprocessing software, the build angles of the restorations were arranged at $0^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, and $90^{\circ}$ and support was added and resultant structure was sliced to a thickness of $100{\mu}m$. Processed restorations were printed with digital light processing type 3D printer using poly methyl meta acrylate-based resin. After washing and post-curing, compressive loading was applied at a speed of 1 mm/min on a metal jig fixed to a universal testing machine. The maximum pressure at which fracture occurred was measured. For the statistical analysis, build direction was set as the independent variable and fracture strength as the dependent variable. One-way analysis of variance and Tukey's post hoc analysis was conducted to compare fracture strength among groups (${\alpha}=0.05$). Result: The mean flexural strength of provisional restoration 3D printed with the build direction of $0^{\circ}$ was $1,053{\pm}168N$; it was $1,183{\pm}188N$ at $30^{\circ}$, $1,178{\pm}81N$ at $45^{\circ}$, $1,166{\pm}133N$ at $60^{\circ}$, and $949{\pm}170N$ at $90^{\circ}$. The group with a build direction of $90^{\circ}$ showed significantly lower flexural strength than other groups (P<0.05). The flexural strength was significantly higher when the build direction was $30^{\circ}$ than when it was $90^{\circ}$ (P<0.01). Conclusion: Among the build directions $0^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, and $90^{\circ}$ set for 3D printing of fixed dental prosthesis, an orientation of $30^{\circ}$ is recommended as an effective build direction for 3D printing.

• Journal of Digital Convergence
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• v.17 no.6
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• pp.229-238
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• 2019

This study investigated the relationship between ego-resilience, Nunchi, self-leadership, and communication competency of Health Majors Students in Studying for TOEIC(HMSST) and analyzed the convergent influence on communication competency. For collection data, this study distributed self-administered questionnaires from November 1 to November 30, 2018 and the questionnaires were distributed to randomly selected 280 health majors students in TOEIC class from colleges located in J area. The survey showed that the communication competency was positively correlated with ego-resilience, Nunchi and self-leadership. The covariance structure analysis showed that the higher ego-resilience, the higher Nunchi and the higher self-leadership tend to increase communication competency. The results of the study indicate that the efforts to increase ego-resilience, Nunchi and self-leadership will improve communication competency of HMSST. These results are expected to be utilized in educational support and mediation to enhance the communication competency among HMSST. In the following study, the research on the additional factors which may influence on communication competency will be needed.