• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1260-1283
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• 2019

Low earth orbit (LEO) satellite broadband network is a crucial part of the space information network. LEO satellite constellation design is a top-level design, which plays a decisive role in the overall performance of the LEO satellite network. However, the existing works on constellation design mainly focus on the coverage criterion and rarely take network performance into the design process. In this article, we develop a unified framework for constellation optimization design in LEO satellite broadband networks. Several design criteria including network performance and coverage capability are combined into the design process. Firstly, the quality of service (QoS) metrics is presented to evaluate the performance of the LEO satellite broadband network. Also, we propose a network stability model for the rapid change of the satellite network topology. Besides, a mathematical model of constellation optimization design is formulated by considering the network cost-efficiency and stability. Then, an optimization algorithm based on non-dominated sorting genetic algorithm-II (NSGA-II) is provided for the problem of constellation design. Finally, the proposed method is further evaluated through numerical simulations. Simulation results validate the proposed method and show that it is an efficient and effective approach for solving the problem of constellation design in LEO satellite broadband networks.

• Quality Improvement in Health Care
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• v.28 no.1
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• pp.2-13
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• 2022

Purpose: This study assessed the status of the Development and Utilization of critical pathways (CP) in South Korea. Methods: We surveyed 195 hospitals obtained on the Korean Hospital Association website. Data were collected using structured questionnaires for staff members in charge of CP management personnel in these hospitals. The questionnaire included CP developed by the institutions, the coverage rates and completion rates of CP in the current year, and management indicators related to CP. The questionnaire also included CP support systems and content within the institutions and questions regarding the advantages of CP utilization and obstacles associated with the CP development process. Results: Analysis of the responses from 70 hospitals (35.9% response rate) showed that a total of 1,370 CP sets were developed. The number of CP related to surgery departments was 365 (26.6%), and CP related to surgery and procedure was 1,093 (79.8%), respectively. The CP coverage rate was the most frequently used indicator to monitor the effect of CP (97.1%), followed by the completion rate (90.0%) and the length of stay in hospital (61.4%). CP managers reported that CP were highly useful for communication (3.39±0.493) and accurate information provision (3.39±0.491). The perception that CP violated doctors' autonomy in treatment was relatively low (2.87±0.645). Conclusion: It is necessary to establish an infrastructure in hospitals for CP. CP can facilitate communication and provide accurate information.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.178-178
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• 2010

With the scaling down of ULSI(Ultra Large Scale Integration) circuit of CMOS(Complementary Metal Oxide Semiconductor)based electronic devices, the electronic devices become more faster and smaller size that are promising field of semiconductor market. However, very narrow line width has some disadvantages. For example, because of narrow line width, deposition of conformal and thin barrier is difficult. Besides, proportion of barrier width is large, thus resistance is high. Conventional PVD(Physical Vapor Deposition) thin films are not able to gain a good quality and conformal layer. Hence, in order to get over these side effects, deposition of thin layer used of ALD(Atomic Layer Deposition) is important factor. Furthermore, it is essential that copper atomic diffusion into dielectric layer such as silicon oxide and hafnium oxide. If copper line is not surrounded by diffusion barrier, it cause the leakage current and devices degradation. There are some possible methods for improving the these secondary effects. In this study, TaNx, is used of Tertiarybutylimido tris (ethylamethlamino) tantalum (TBITEMAT), was deposited on the 24nm sized trench silicon oxide/silicon bi-layer substrate with good step coverage and high quality film using plasma enhanced atomic layer deposition (PEALD). And then copper was deposited on TaNx barrier using same deposition method. The thickness of TaNx was 4~5 nm. TaNx film was deposited the condition of under $300^{\circ}C$ and copper deposition temperature was under $120^{\circ}C$, and feeding time of TaNx and copper were 5 seconds and 5 seconds, relatively. Purge time of TaNx and copper films were 10 seconds and 6 seconds, relatively. XRD, TEM, AFM, I-V measurement(for testing leakage current and stability) were used to analyze this work. With this work, thin barrier layer(4~5nm) with deposited PEALD has good step coverage and good thermal stability. So the barrier properties of PEALD TaNx film are desirable for copper interconnection.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.2
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• pp.121-135
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• 2016

The present study is an analysis of the monitoring results of the four areas that underwent the experimental construction of Straw-net+seedspray, Vegetation media spray method(t=2cm), and Vegetation media spray method(t=3cm), with the purpose of selecting the adequate revegetation of cutting slopes in weathered granite soil. Cutting slopes are mostly designed in the Straw-net+seedspray method, but since weathered granite soil slopes tend to have an infertile soil quality that runs down, it is difficult for seed germination and growth. It is difficult to apply Straw-net+seedspray to weathered granite soil slopes considering the germination rate and coverage rate of the Straw-net+seedspray method, which accompanies erosion and scouring. The final conclusions are summarized as follows. First, Straw-net+seedspray has difficulty recruiting plants to infertile weathered granite soil, which results in a lower coverage rate and fewer species, so it is not adequate construction method. Second, Vegetation spraying methods with wet media are more advantageous in early revegetation. The wet construction methods are faster than the dry construction methods in terms of early germination and its early growth are more excellent. Third, when constructing Vegetation spray methods with dry media, it were more advantageous if the thickness was thicker. When the soil-media is thicker, the soil is resilient to droughts, so the thickness must be flexibly applied according to the soil quality and slant of the weathered granite soil slope. The present study is a monitoring result for some areas of Gangwon-do, so its results may differ from other areas.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10A
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• pp.1461-1472
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• 2000

Recently, the mobile users seem to be rapidly increasing and then the capacity limit will be reached at close hand. In these situations, to provide them with good quality of service in the coming future, newly planned cell design is needed. In the next generation mobile communication systems, namely IMT-2000, good quality services will be possible only by designing the cell structure hierarchically with the help of appropriate cell planning. In the research process, the standardization reports on the future mobile cellular IMT-2000 system (3GPP) are investigated and the parameters, that are essential to cell planning, are also researched. Modeling of IMT-2000 radio link and the numerical analysis on that make it possible to calculate the forward/reverse link budget, system capacity call blocking probability Erlang capacity and cell coverage. In planning the cell of IMT-2000 system, various parameters are considered, such as hierarchical cell structure, number of users, data service forms and propagation area environments. From the results, efficient cell planning methods are proposed. Through this thesis efficient cell planning and maximum capacity will be achieved in the beginning of commercial IMT-2000 service.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.449-458
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• 2010

The e-Learning quality assurance is a part of responsibility for education in latest information age, and should be understood as a basic direction for qualitative enhancement rather than quantifiable expansion. In such a context, this study sought to survey latest trends of e-Learning quality assurance activities deployed around overseas countries, so that it could give possible implications on how to plan and perform e-Learning quality assurance in Korea. So, this study focused on surveying actual conditions, coverage, target and useful indices of e-Learning quality assurance activities deployed by 9 institutions across 5 countries, and characterizing those activities across 5 countries. As a result, this study could find out its implications such as acquisition of various resources available for e-Learning, nationwide consolidation of e-Learning quality assurance activities, development of specialists in e-Learning quality assurance, and choice and focus for e-Learning quality assurance system. In other words, it was found that e-Learning quality assurance should be approached from nationwide standpoint in the interest of better educational quality, rather than from viewpoint of task.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.9
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• pp.275-284
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• 2016

The software used in the nuclear safety field has been ensured through the development, validation, safety analysis, and quality assurance activities throughout the entire process life cycle from the planning phase to the installation phase. However, this evaluation through the development and validation process needs a lot of time and money, and there are limitations to ensure that the quality is improved enough. Therefore, the effort to calculate the reliability of the software continues for a quantitative evaluation instead of a qualitative evaluation. In this paper, we propose a reliability evaluation method for the software to be used for a specific operation of the digital controller in a nuclear power plant. After injecting weighted faults in the internal space of a developed controller and calculating the ability to detect the injected faults using diagnostic software, we can evaluate the software reliability of a digital controller in a nuclear power plant.

• Journal of Distribution Science
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• v.20 no.11
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• pp.19-31
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• 2022

Purpose: This research aims to analyze the educational potential and students' satisfaction with the quality of education services distribution in Kazakhstani universities. The conceptual review shows that very few studies on regional development have been able to determine the level of satisfaction with the quality of educational services depending on the university's location. Research design, data, and methodology: The research methodology is divided into two approaches descriptive analysis and qualitative data analysis. The current educational situation and the distribution of educational services in the largest Kazakh universities were studied based on the proposed approaches' use. Statistical data are taken for indicators of educational potential for 2010-2020 from the Bureau of National Statistics. The primary data were collected based on a survey for 2021-2022 in five regions of Kazakhstan. Results: The results showed that there is a gender gap between men and women and regional disparities between the regions of Kazakhstan in the coverage of higher education. The results of the sociological survey revealed that the quality of educational services depends on the territorial location of the university. Conclusions: Based on the results of the assessment of educational potential and educational services, policy recommendations and further research in this area were proposed.

• Journal of the Korean Home Economics Association
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• v.39 no.12
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• pp.51-63
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• 2001

With the development of information technology, more and more internet sites are available to consumers. Increasing on the interests of diet and health in modem society, there are numerous internet sites dealing with food, nutrition and health. Considering the importance and expected roles of internet sites in information dissemination in the future world, it is important to put more efforts to encourage internet sites with more accurate an useful information. Up to present, not much work has been done on quality analysis and evaluation of the internet information. This study aimed to develop a model to evaluate and rank the internet information according to its quality so that consumers can be guided toward correct information source. Three models were adapted from the literature for pilot study to develop a model suitable for evaluation of contents of sites related to food and nutrition information. From the pilot study, a evaluation model was developed with criteria more relevant to Korean internet site by expert panel. Evaluation criteria of the model is authority, accuracy, objectivity, coverage, and user-friendliness. For the objective and systematic evaluation, scores were assigned totaling maximum 100 point to each evaluation criteria factors. The model developed in this study could be used as one for other internet sites in area other than food and nutrition.

• Journal of the Korean Ceramic Society
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• v.44 no.3 s.298
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• pp.142-146
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• 2007

High-quality one-dimensional GaN nanorods and nanowires were synthesized on Ni-coated c-plan sapphire substrate using halide vapor-phase epitaxy (HVPE). Their structure and optical properties were investigated by X-ray diffraction, scanning and transmission electron microscopy, and photoluminescence techniques. Full substrate coverage of densely packed, uniform, straight and aligned one-dimensional GaN nanowires with a diameter of 80nm were grown at $700{\sim}900^{\circ}C$. The X-ray diffraction patterns, transmission electron microscopic image, and selective area electron diffraction patterns indicate that the one-dimensional GaN nanostructures are a pure single crystalline and preferentially oriented in the [001] direction. We observed high optical quality of GaN nanowires by photoluminescence analysis.