• Journal of Fisheries and Marine Sciences Education
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• v.26 no.6
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• pp.1261-1277
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• 2014

In recently, attracting foreign students are very active in lots of universities of South Korea. According to trend, foreign students who are studying in Korea have increased steadily. The programs to support and help them for adaptation of the university and academic success are rising though, on account of language barrier, it seems not easy to adapt to those people who finished studying korean language training that roles incubator and entered their major. More over, to expect personal training for them by professors is also difficult because of short of educational or executive and bankroll support in reality. Therefore it became a social issue about managing foreign students of South Korea. This study aimed to analyse the difficulties of learning from chinese international student's view. For this, we analysed focus group interview which intended 16 chinese foreign students and the collected data through reflective journal record using Nvivo program. In the results of focus group interview, learning difficulties of chinese foreign students are itemized 4 sections of personal aspect, environmental aspect, educational contents' aspect and educational methodic aspect. It is subdivided 11 sections and identified of requirement for studying support corresponding each part of difficulties. This research finding will be able to expect to provide a suggestion to looking for options for learning support plan of chinese foreign students.

• Korean Journal of Optics and Photonics
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• v.32 no.4
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• pp.153-162
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• 2021

In this article, the design of a variable F-number and triple magnification infrared optical system is described. That is a two-in-one optical system that combines an infrared search and track (IRST) system and an electro-optical tracking system (EOTS), where an afocal optical system is added to the IRST optical system designed already. The performance target is determined by analyzing system performance, and then the specification in the optical system design is calculated. This optical system contains a warm stop making it possible that one optics has two different F/# by cutting the size of aperture, and that is designed to suit this optics. The system satisfies the requirement such as a modulation transfer function (MTF). For operational assessment, the movement of the focusing lens group is analyzed over the change of temperature and target distance. By using this optical system, it is possible to develop equipment having two functions, infrared searching and electro-optical tracking.

• Korean Journal of Community Nutrition
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• v.24 no.4
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• pp.309-320
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• 2019

Objectives: This study was undertaken to compare dietary life of the elderly living alone and in a family, and to compare differences based on gender, for the 2013-2016 Korea National Health and Nutrition Examination Survey (KNHANES). Methods: The subjects included 2,612 elderly people aged over 65 years who participated in the health survey, health examination and nutrition survey. Subjects on a diet therapy were excluded. This study analyzed the general characteristics, dietary habits, daily energy and nutrient intakes, CPF ratio, estimated average requirement (EAR), nutrient adequacy ratio (NAR) and mean adequacy ratio (MAR), index of nutrient quality (INQ), and food consumption of the elderly living alone and in a family. We also compared the differences based on gender. Results: Daily intake of food, water, dietary fiber, potassium, retinol, and riboflavin were low in the male elderly subjects living alone. The elderly living with family revealed higher NAR and MAR as compared to the elderly living alone. Although all MAR values were <1, the elderly living alone had lower values. Considering the intake of food, the consumption of seaweed, fish and shellfish, and oils (animal) was higher in elderly men living with families, whereas women living with families consumed more vegetables, fruits, seaweeds and seafood, as compared to their counterparts living alone. Furthermore, analyzing the foods consumed by the elderly people living alone, female subjects consumed more seaweed, milk and animal oil as compared to male subjects. Conclusions: The results of this study indicate that the elderly living alone have poor nutrient intake as compared to the elderly living with families. Based on this research data, we recommend that it is necessary to improve the health and nutritional status of the elderly living alone.

• Oral Biology Research
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• v.42 no.4
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• pp.222-227
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• 2018

The purpose of this study was to determine the cause and risk factors of removing bone plateby investigating and analyzing 359 patients who underwent reduction of fracture or orthognathic surgery with bone plate insertion over the past 3 years. Patients were evaluated with respect to age, smoking status, reason for insertion of plates, the numbers of inserted plates, sites of insertion, time between insertion and removal, reasons for removal of plates. The removal rate of bone plates was 33.1%. Of these, 17.0% of patients had clinical symptoms which led to remove plates. The removal rate of men was 29.9% and the rate of women was 39.2%. There were high removal rates from less than 20s (45.8%) and 20s (34.4%) those who are relatively young age group. On the other hand people in their 50s had a removal rate of 27.8% which was higher than those in their 60s with a rate of 20.7%. The removal rate of bone plate inserted into the mandible was 33.5%, and the removal rate of bone plate inserted into the maxilla was 34.7%. The mean period between the insertion and removal of bone plate was 10.9 months. The main reason for the removal of bone plate was the patient's requirement (44.5%). The most common cause of clinical symptoms was infection (22.7%). Infection was manifested within about a year and led to the plate being removed. Therefore, lowering the possibility of infection after surgery could decrease the removal rate of bone plate.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.12
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• pp.4946-4960
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• 2020

In a device-to-device (D2D) underlaid cellular network, there exist two types of co-channel interference. One type is inter-layer interference caused by spectrum reuse between D2D transmitters and cellular users (CUEs). Another type is intra-layer interference caused by spectrum sharing among D2D pairs. To mitigate the inter-layer interference, we first derive the interference limited area (ILA) to protect the coverage probability of cellular users by modeling D2D users' location as a Poisson point process, where a D2D transmitter is allowed to reuse the spectrum of the CUE only if the D2D transmitter is outside the ILA of the CUE. To coordinate the intra-layer interference, the spectrum sharing criterion of D2D pairs is derived based on the (signal-to-interference ratio) SIR requirement of D2D communication. Based on this criterion, D2D pairs are allowed to share the spectrum when one D2D pair is far from another sufficiently. Furthermore, to maximize the energy efficiency of the system, a resource allocation scheme is proposed according to weighted graph coloring theory and the proposed ILA restriction. Simulation results show that our proposed scheme provides significant performance gains over the conventional scheme and the random allocation scheme.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.2
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• pp.85-96
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• 2022

The study is aimed to investigate the features and socio-economic background of farmland consolidation project with medium-sized paddy plot at irrigation associations during the Japanese colonial period in Korea. Most of farmland consolidation works in the 1940s was composed of independent irrigation and drainage ditches along the short side of field plot. However, the number of farm roads at farmland consolidation zone was much smaller than number of irrigation ditches to decrease reduction in farmland area. The standard field plot was medium-sized (about 20-40 ares) in Korea but small-sized (about 10 ares) in Japan in this period. As the result of farmland consolidation works, the unit water requirement was increased to 0.0035 m³/s/ha, and the unit area drainage discharge was over 2.0 m³/s/km² in many cases. The farmland consolidation with medium-sized plot have been spread under the colonial landlord system, where major landlords occupied a large share of farmland and managed corporate farming to gain more benefit. The reasons for spread of farmland consolidation with medium-sized plot may be as follows: high net profit ratio, an increase in land price, and labor savings in rice farming. The farmland consolidation with medium-sized plot in the colonial period showed intermediate features between the farm consolidation with small-sized plot for an increase in land productivity in Japan and the farm consolidation with medium-sized plot for an increase in labor productivity after the 1960s.

• The Journal of the Korea Contents Association
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• v.22 no.10
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• pp.404-413
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• 2022

As non-face-to-face classes have been adopted as an essential class method in universities after COVID-19, interest in ways to encourage student engagement is increasing. Class engagement is a prerequisite for improving the quality of education, so it is inevitably an even more important requirement in non-face-to-face classes. Therefore, this study examined the efforts and concerns based on the teaching experiences of three professors of D University, which have been operated by mixing non-face-to-face or non-face-to-face classes since 2020. As a result, both professors and students went through trial and error in the early stages of non-face-to-face classes, but over time, it was confirmed that students not only actively expressed their opinions but also voluntarily expanded the class activity. This study is meaningful in that it found the possibility that professors-led classes can develop into learner-participating classes through appropriate harmony between face-to-face and non-face-to-face and the use of various media. Data were collected through an autobiographical method.

• Journal of Soil and Groundwater Environment
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• v.27 no.2
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• pp.24-35
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• 2022

This study was conducted to estimate groundwater demand and supply for agricultural activities in a frequent-drought area that requires implementation of optimal distribution plan utilizing the well-network system (WNS). The WNS has been considered as a viable strategic way of supplying groundwater to farmlands by connecting groundwater wells physically or virtually. The study area heavily relied on groundwater resources for irrigation up to 53% due to a lack of surface water resources. Two kinds of methods, HOMWRS software and FAO approach, were used for estimating irrigation water requirements for paddy and upland fields, respectively. During the latest 10 years (2010~2019), the water requirements was estimated to be 1,106 m³/day. The requirements notably increased to 1,121~4,004 m³/day during active farming season (May to September), which exceeded the total yield capacity of pre-existing groundwater wells (2,356 m³/day) in the area. Detailed and definite determination for groundwater demand and supply helped to determine optimal scale parameters of WNS. The WNS has achieved more balanced distribution of groundwater resources for irrigation over the study area.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.185-185
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• 2023

Agricultural water demand is considered as the major sector of water withdrawal due to irrigation. The majority part of the global agricultural field depends on various irrigation techniques. Therefore, a timely and sufficient supply of water is the most important requirement for agriculture. Irrigation is implemented in different ways in various land surface models, it can be modeled empirically based on observed irrigation rates or by calculating water supply and demand. Certain models can also calculate the irrigation demand as per the soil water deficit. In these implementations, irrigation is typically applied uniformly over the irrigated land regardless of crop types or irrigation techniques. Whereas, the latest version of Community Land Model (CLM) in the Community Terrestrial Systems Model (CTSM) uses a global distribution map of irrigation with 64 crop functional types (CFTs) to simulate the irrigation water demand. It can estimate irrigation water withdrawal from different sources and the amount or the areas irrigated with different irrigation techniques. Hence, we set up the model for the simulation period of 16 years from 2000 to 2015 to analyze the global irrigation demand at a spatial resolution of 1.9° × 2.5°. The simulated irrigation water demand is evaluated with the available observation data from FAO AQUASTAT database at the country scale. With the evaluated model, this study aims to suggest new sustainable scenarios for the ratios of irrigation water withdrawal, high depending on the withdrawal sources e.g. surface water and groundwater. With such scenarios, the CFT maps are considered as the determining factor for selecting the areas where the crop pattern can be altered for a sustainable irrigation water management depending on the available withdrawal sources. Overall, our study demonstrate that the scenarios for the future sustainable water resources management in terms of irrigation water withdrawal from the both the surface water and groundwater sources may overcome the excessive stress on exploiting the groundwater in major river basins globally.

• Journal of the Korea Society for Simulation
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• v.19 no.1
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• pp.153-160
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• 2010

Most part of errors in software development process are included during the stage of requirements definition and design. And correction or elimination of errors from those stages requires much more efforts and costs than those from the later part of software development process. However, despite of the importance of the validation of requirement definition and design stages, several kinds of problem have made it hard to be done successfully. Therefore, in this paper, we introduce a novel validation process for the preliminary design stage. The validation process is based on simulations of model and it can be used to validate requirements and model simultaneously. Models in the validation process will take only the behavior of software and be built on Ptolemy framework. The usability of our validation process is confirmed with a case study over DNS system environment. And the result of simulation shows well-known errors or vulnerabilities can be found with simulations of model which has the behavior of software. This means our validation process can be used as a process to validate requirements and models during the early stage of software development process.