• The Journal of the Korea Contents Association
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• v.17 no.9
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• pp.486-497
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• 2017

Travel voucher for low-income or social disadvantaged groups forms a part of social policies in Korea. The policy can not only provide an opportunity of travel experiences for the socially weak, but also enhance their family capital and social capital. Thus, the travel voucher policy can be beneficial for the participants and their society. However, little research evidence of its evaluation and challenges/benefits exists. In practice, one of the biggest problems is an attrition of travel voucher winners which is to decrease a cost-effect of the travel voucher policy and to increase unnecessary waste of both the federal and human resources. Thus more research is needed to answer the questions why some of winners abandon to go to travel by the voucher, and who is the seceder? In this context, the study empirically examines the attrition propensity for the winners of 2011 Seoul travel voucher from 1,632 respondents and second data from Korea Tourism Organization. This research found that total education years of travel voucher winners have a significant effect on using their voucher. Implications and alternative policies for government policy makers and administrators are discussed by the analyzed results.

• Fisheries and Aquatic Sciences
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• v.26 no.5
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• pp.305-317
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• 2023

Ethiopia is branded as the Water Tower of Africa because of its abundant inland water bodies that may be used sustainably to boost the economy. This review article's goal is to examine the current status and future potential of Ethiopia's fisheries, with a special focus on reservoirs. There are 200 known fish species (194 native, 40 endemic, and 11 exotic) in in Ethiopia's inland water. Ethiopia's fish production has increased by a factor of more than five in the past three decades (3,500 tons in 1983 to 15,681 tons in 2000 and 18,058 tons in 2010). However, fish produced in reservoirs is too low (8,059 t/year). The current fish harvests from reservoirs are significantly below the predicted potential yield, accounting for only 35% of the calculated fish production capacity. In this review, 14 potential reserves were revealed. A total of 48 fish species have been reported in these, of which 26 species (or around 54%) are present in Alwero reservoir. 19 of the 48 species that have been officially recognized belong to the Cyprinidae family and made up nearly 40% of the fish population in Ethiopian reservoirs. There has been, however, a decline in the productivity of Ethiopia's reservoir fish. Hence, actively start fishing in the numerous reservoirs that have been neglected yet, link the potential of fisheries and the benefits of the fish farming supply chain, let's begin building several other reservoirs similar to the Grand Ethiopian Renaissance Dam and beginning mechanized-based fish harvesting.

• Membrane Journal
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• v.34 no.2
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• pp.114-123
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• 2024

Hydrogen isotopes can be categorized into light hydrogen, heavy hydrogen, and tritium based on the number of neutrons, each of which is used in specific fields. Specifically, deuterium is of interest in the electronics industry, nuclear energy industry, analytical technology industry, pharmaceutical industry, and telecommunications industry. Conventional methods such as cold distillation, thermal cycling absorption processes, Girdler sulfide processes, and water electrolysis have their own advantages and disadvantages, leading to the need for alternative technologies with high separation and energy efficiency. In this context, membrane-based hydrogen isotope separation is one of the promising solutions to reduce energy consumption. In this review, we will present the state-of-the-art in hydrogen isotope separation using membranes and their operating principles. The technology for separating hydrogen isotopes using membranes is just beginning to be conceptualized, and many challenges remain to be overcome. However, if achieved, the economic benefits are expected to be significant. We will discuss future research directions for this purpose.

• Convergence Security Journal
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• v.23 no.5
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• pp.21-27
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• 2023

In the cloud computing environment, servers and applications can be set up within minutes, and recovery in case of fail ures has also become easier. Particularly, using virtual servers in the cloud is not only convenient but also cost-effective compared to the traditional approach of setting up physical servers just for temporary services. However, most of the und erlying networks and security systems that serve as the foundation for such servers and applications are primarily hardwa re-based, posing challenges when it comes to implementing cloud virtualization. Even within the cloud, there is a growing need for virtualization-based security and protection measures for elements like networks and security infrastructure. This paper discusses research on enhancing the security of cloud networks using network virtualization technology. I configured a secure network by leveraging virtualization technology, creating virtual servers and networks to provide various security benefits. Link virtualization and router virtualization were implemented to enhance security, utilizing the capabilities of virt ualization technology. The application of virtual firewall functionality to the configured network allowed for the isolation of the network. It is expected that based on these results, there will be a contribution towards overcoming security vulnerabil ities in the virtualized environment and proposing a management strategy for establishing a secure network.

• Journal of Internet Computing and Services
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• v.20 no.4
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• pp.1-11
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• 2019

A Blockchain-based access control technology is one of the various use cases of blockchain and is used in many areas to transparently transfer and manage ownership of data between users without the trusted third party. The characteristics of transparency, Irreversibility, and decentralization provided by the public blockchain help to offer new benefits that existing access control technologies did not offer. However, various security issues facing the current blockchain are raising the issue of the safety of the technology. Therefore, in this paper, we analyze an overview of the blockchain-based access control technology and solutions of the security challenges faced. Moreover, we further present solutions that are not affected by the blockchain trilemma and models of access control technology based on them.

• Journal of the Korean Society for Library and Information Science
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• v.56 no.1
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• pp.321-345
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• 2022

Public libraries have been facing new challenges as the number of channels providing information resources has been increasing due to information and communication technology development. The perception of public libraries of the general public is that they should continue to play a substantial role in information services. However, the libraries' environments are changing, and the public's needs are diversifying, so public libraries also need to differentiate themselves from other organizations that provide similar services. This paper proposes branding as a solution to create differentiation. The study conducted a questionnaire survey with Koreans in their 20s. A series of statistical tests with the survey data showed the impact of the brand association elements on customer satisfaction and brand loyalty and identified unique factors in public libraries. For example, Brand associations such as material-based services, benefits, and attitude affected both dependent variables. On the other hand, the non-product association such as space/place images did not. Based on these findings, we provided implications for introducing branding in public libraries.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.246-246
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• 2023

Multi-purpose dams are operated accounting for both physical and socioeconomic factors. This study aims to evaluate the utility of a deep learning algorithm-based model for three multi-purpose dam operation (Seomjin River dam, Juam dam, and Juam Control dam) in Seomjin River. In this study, the Gated Recurrent Unit (GRU) algorithm is applied to predict hourly water level of the dam reservoirs over 2002-2021. The hyper-parameters are optimized by the Bayesian optimization algorithm to enhance the prediction skill of the GRU model. The GRU models are set by the following cases: single dam input - single dam output (S-S), multi-dam input - single dam output (M-S), and multi-dam input - multi-dam output (M-M). Results show that the S-S cases with the local dam information have the highest accuracy above 0.8 of NSE. Results from the M-S and M-M model cases confirm that upstream dam information can bring important information for downstream dam operation prediction. The S-S models are simulated with altered outflows (-40% to +40%) to generate the simulated water level of the dam reservoir as alternative dam operational scenarios. The alternative S-S model simulations show physically inconsistent results, indicating that our deep learning algorithm-based model is not explainable for multi-purpose dam operation patterns. To better understand this limitation, we further analyze the relationship between observed water level and outflow of each dam. Results show that complexity in outflow-water level relationship causes the limited predictability of the GRU algorithm-based model. This study highlights the importance of socioeconomic factors from hidden multi-purpose dam operation processes on not only physical processes-based modeling but also aritificial intelligence modeling.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.12
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• pp.2549-2558
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• 2015

The non-orthogonal multiple access (NOMA) is one of the fledging paradigms which next generation radio access technologies are sprouting toward. The NOMA with superposition coding (SC) in the transmitter and successive interference cancellation (SIC) at the receiver comes with many desirable features and benefits over orthogonal multiple access (OMA) such as orthogonal frequency division multiple access (OFDMA) adopted by Long-Term Evolution (LTE). In this paper, we study the recent research trends on NOMA in 5G systems. We discuss the basic concept of NOMA and explain its aspects of importance for future radio access. Then, we provide a survey of the state of the art in NOMA for 5G systems in a categorized manner. Further, we analyze the NOMA performances with numerical examples; and provide some avenues for future research on NOMA on a set of open issues and challenges.

• Journal of Korean Biological Nursing Science
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• v.23 no.1
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• pp.72-82
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• 2021

Purpose: This study used a mixed methods research design in an attempt to verify the effects of robot-assisted rehabilitation on the gait ability of stroke patients with hemiplegia, and thereby further understand the benefits and challenges of stroke patients' experiences relying on robot-assisted rehabilitation. Methods: An exploratory sequential mixed methods study design was used in order to combine both quantitative and qualitative data. For the quantitative data collection, a total of 30 stroke patients with hemiplegia were recruited from one rehabilitation hospital. Qualitative data were collected through individual interviews using semi-structured questionnaires for a group of 15 patients who were currently undergoing robot-assisted rehabilitation. The data were analyzed through qualitative content analysis. Results: As a result of the quantitative analysis, there were significant differences between the two groups in terms of daily living activity patterns, total number of steps, and average walking speed. As a result of the qualitative analysis, the four main themes derived consisted of, 'curiosity about the usage of robot-assisted rehabilitation,' 'pleasure experienced while using the robots,' 'insufficient information about robots,' and 'a lack of education about robot-assisted rehabilitation.' Conclusions: Robot-assisted rehabilitation had a significant effect on the walking ability of stroke patients with hemiplegia. Additionally, stroke patients with hemiplegia experienced difficulty during the course of their robot-assisted rehabilitation, due to a lack of sufficient information on correct usage techniques. These quantitative and qualitative findings could provide the basic foundation for the development of an educational program on robot-assisted rehabilitation.

• Nuclear Engineering and Technology
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• v.55 no.12
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• pp.4367-4381
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• 2023

Nuclear power plants are increasingly being equipped with digital I&C systems. Although some probabilistic safety assessment (PSA) models for the digital I&C of nuclear power plants have been constructed, there is currently no specific internationally agreed guidance for their modeling. This paper presents an initiative by the OECD Nuclear Energy Agency called "Digital I&C PSA - Comparative application of DIGital I&C Modelling Approaches for PSA (DIGMAP)", which aimed to advance the field towards practical and defendable modeling principles. The task, carried out in 2017-2021, used a simplified description of a plant focusing on the digital I&C systems important to safety, for which the participating organizations independently developed their own PSA models. Through comparison of the PSA models, sensitivity analyses as well as observations throughout the whole activity, both qualitative and quantitative lessons were learned. These include insights on failure behavior of digital I&C systems, experience from models with different levels of abstraction, benefits from benchmarking as well as major contributors to the core damage frequency and those with minor effect. The study also highlighted the challenges with modeling of large common cause component groups and the difficulties associated with estimation of key software and common cause failure parameters.