• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.2
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• pp.107-120
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• 2021

Electric-powered distributed propulsion aircraft possess a complex wake flow and mutual interference with the airframe, due to the use of many propellers. Accordingly, in the early design stage, rapid aerodynamic and load analysis considering the effect of propellers for various configurations and flight conditions are required. In this study, an efficient panel-based aerodynamic analysis method that can take into account the propeller effects is developed and validated. The induced velocity field in the region of propeller wake is calculated based on Actuator Disk Theory (ADT) and is considered as the boundary condition at the vehicle's surface in the three-dimensional steady source-doublet panel method. Analyses are carried out by selecting an isolated propeller of the Korea Aerospace Research Institute (KARI)'s Quad Tilt Propeller (QTP) aircraft and the propeller-wing configuration of the former experimental study as benchmark problems. Through comparisons with the results of computational fluid dynamics (CFD) based on actuator methods, the wake velocity of propeller and the changes in the aerodynamic load distribution of the wing due to the propeller operation are validated. The method is applied to the analysis of the Optional Piloted Personal Aerial Vehicle (OPPAV) and QTP, and the practicality and validity of the method are confirmed through comparison and analysis of the computational time and results with CFD.

• Journal of Legislation Research
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• no.54
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• pp.155-192
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• 2018

As the 'hyper-connected society' has emerged through the 'Fourth Industrial Revolution, public interests as well as social dangers have increased. Above all, the risk of infringement of information, including confidential personal information, is dramatically increasing. As the hyper-connected society has been realized, even if only one of the internet devices is hacked, there would be a danger that the ripple effect of such a hacking spreads to the whole network. Therefore, the necessity and importance of information security, including cybersecurity, has been increasing. In other words, the stability of cyberspace and internet space is becoming more important. As a result, the Korean government is seeking to build a legal system related to information security, which would be able to cope with the information infringement problem in the hyper-connected society. However, it seems that the government is still struggling with the direction of building such a legal system. In this context, a comparative review examining the legal systems of advanced foreign countries will provide meaningful implications as to what kinds of legal policies we should devise and implement for information security. In particular, the U.S. legislative act that actively responds to the cybersecurity violations is worthy of reference. For this reason, this article systematically analyzes the current status of the U.S. cybersecurity laws. Especially, this article focuses on the "Cybersecurity Information Sharing Act of 2015"(hereinafter "CISA"), that was recently enacted by the U.S. congress. The CISA prescribes the systemic and detailed information-sharing between national and private entities. The CISA, that actively promotes information-sharing, is full of suggestions for us, in that information-sharing is an effective way to properly realize information security in today's hyper-connected society.

• 한국사회정책
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• v.23 no.1
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• pp.95-123
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• 2016

As Korean society grows rapidly older, a systematic analysis of the determinants of labor supply behavior among the elderly becomes a prerequisite for designing more effective senior employment policies and income security regime for the elderly. Literatures review shows that a majority of previous researches have been ignoring the problem of "endogenous predictor" especially when it comes to the estimation of the effects of the two key variables, education and non-labor income, on labor supply decisions among older people. They have failed to take into consideration the unobserved heterogeneities which might affect both labor supply decisions of the elderly and their levels of education and non-labor income, which means, according to some econometric literatures, that the estimated coefficients of the two predictors can be inconsistent. The paper tries to redress the endogeneity problem by employing a panel logit model with data from the 1st. to 4th. wave of the KLoSA(Korean Longitudinal Survey of Ageing) to estimate the effects of key predictors on the probability of getting jobs among older people(ages of 60 or older). Both a random effects and a fixed effects model reaffirms that non-labor income has a negative effect on the chances of being employed. And a random effects model shows that the effect of education is also negative, as has frequently been reported by previous studies. That means the effects of education and non-labor income on elderly employment remain negative after the effect of unobserved heterogeneities is controled for and the problem of endogenous predictors is redressed through an appropriate panel data analysis. These findings mean, in turn, that when Korean baby-boomers, who had acquired an unprecedentedly higher level of education and were expected to enjoy ever-larger amount of non-labor income than their preceding generations, retires in near future, their incentives to work will become much weaker and the lack of labor-force and the burden of financing increased public pension expenditure will become more troublesome. The paper concludes with recommending some policy initiatives helpful to solve these expected problems.

• (The)Study of the Eastern Classic
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• no.33
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• pp.231-252
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• 2008

This study is to investigate on focus of his political position change to build up his the real form about Park je sang(朴堤上) who had taken an active part within Shila nulgi king(訥祗王) period on base of previous park je sang' study results. that is, this study took attention about excellent capability by diplomat who had shown his diplomatic ability in complicated and international fields of three countries, and about process of entrance on central political fields by private capability in sap lang(?良) district in relation with building up the real form of park je sang. As result, by means of few investigations about park je sang who had taken an active part, we looked into process how local power man in sap lang(?良) district had built up his position to jin-gol(眞骨) status with strategic location of sap lang(?良) district on shila history within Shila nulgi king period. I think that we found valuable means from figures of a district society in process how Shila had grown with a country of centralizing power.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.6A
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• pp.63-73
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• 2008

RFID(Radio Frequency IDentification) system is an automated identification system that basically consists of tags and readers and Back-End-Databases. Tags and Readers communicate with each other by RF signal. As a reader can identify many tags in contactless manner using RF signal, RFID system is expected to do a new technology to replace a bar-code system in supply-chain management and payment system and access control and medical record and so on. However, RFID system creates new threats to the security of systems and privacy of individuals, Because tags and readers communicate with each other in insecure channel using RF signal. So many people are trying to study various manners to solve these problems against attacks, But they are difficult to apply to RFID system based on EPCglobal UHF Class-1 Generation-2 tags. Recently, Chien and Chen proposed a mutual Authentication protocol for RFID conforming to EPCglobal UHF Class-1 Generation-2 tags. we discover vulnerabilities of security and inefficiency about their protocol. Therefore, We analyze vulnerabilities of their protocol and propose an efficient mutual authentication protocol that improves security and efficiency.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.6
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• pp.97-109
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• 2010

Although the primary liability for online copyright infringement may fall on the individual who illegally copies, transfers, and/or distributes the copyrighted content, the issue of indirect liability for Online Service Providers (OSPS) that provide a channel for the distribution of illegal content has recently come under the spotlight. Currently, in an effort to avoid liability for indirect copyright infringement and improve their reputation, most OSPs have voluntarily applied filtering technology. Under the Copyright Act of Korea, special types of OSPS including P2P and Web-based Hard Drive (WebHard) are required to incorporate filtering technology, and may be charged with penalties if found without one. However, despite the clear need for filtering mechanisms, several arguments have been set forth that question the efficacy and appropriateness of the system. As such, this paper discusses the liability theory adopted in the US. -a leader in internet technology development-and analyzes the scope of liability and filtering related regulations in our copyright law. In addition, this paper considers the current applications of filtering as well as limits of the applied filtering technology in OSPS today. Finally, we make four suggestions to improve filtering in Korea, addressing issues such as clarifying the limits and responsibilities of OSPS, searching for cooperative solutions between copyright holders and OSPS, standardizing the filtering technology to enable compatibility among different filtering techniques, and others.

• Knowledge Management Research
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• v.22 no.1
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• pp.217-242
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• 2021

The purpose of this study is to examine the research trends in the filed of individual knowledge hiding through keyword network analysis. As individuals intentionally hide their knowledge beyond not sharing their knowledge in organizations and the research on knowledge hiding steadily spreads, it is necessary to examine the research trends regarding knowledge hiding behaviors. For keyword network analyses, we collected 346 kinds of 578 keywords from 120 articles associated with knowledge hiding behaviors. We also transformed the keywords to 86 nodes and 667 links by data standardizing criteria and finally analyzed the keyword network among them. Moreover, this study scrutinized knowledge hiding trends by comparing the conceptual model for knowledge hiding based on literature review and the network structure based on keyword network analysis. As results, first, the network centrality degree, knowledge sharing, creativity, and performance was higher than others in Degree, Betweenness, Closeness centrality. Second, this study analyzed ego networks about psychological ownership and individual emotion theoretically associated with knowledge hiding and explored the relationship between variables through comparing with the conceptual model for knowledge hiding. Finally, the study suggested theoretical and practical implications and provided the limitations and suggestions for future research based on study findings.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.633-642
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• 2021

This study explores the online learning experiences of Chinese foreign students in Korea by using the CQR process and method. To gather data, researchers conducted online, in-depth interviews with 15 Chinese university students in Korea who were enrolled in the spring and fall semesters in 2020. After compiling the research, the data were segmented into four domains and 13 categories, with 36 subcategories identified from among foreign students' online learning experiences. The results show that Chinese students perceived the convenience of online classes and personalized learning as its strength, but considered lowered motivation and lack of concentration as weaknesses. Also, they experienced an increase in the amount of learning, spending more time studying online, using personal learning strategies, and getting help from friends and the university's online learning system. Moreover, they experienced difficulties related to class notifications, guidance, and interactions with the instructors. Foreign students studying in Korea need their instructor's facilitation in order to understand and participate in online classes, reinforcing a student's self-directed learning ability, and need appropriate guidance and support in terms of the online class environment.

• Journal of Korea Society of Industrial Information Systems
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• v.25 no.6
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• pp.33-45
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• 2020

This paper aims to look at the perspective that the latest cutting-edge technologies are predicting individual diseases in the actual medical environment in a situation where various types of wearable devices are rapidly increasing and used in the healthcare domain. Through the process of collecting, processing, and transmitting data by merging clinical data, genetic data, and life log data through a user-participating wearable device, it presents the process of connecting the learning model and the feedback model in the environment of the Deep Neural Network. In the case of the actual field that has undergone clinical trial procedures of medical IT occurring in such a high-tech medical field, the effect of a specific gene caused by metabolic syndrome on the disease is measured, and clinical information and life log data are merged to process different heterogeneous data. That is, it proves the objective suitability and certainty of the deep neural network of heterogeneous data, and through this, the performance evaluation according to the noise in the actual deep learning environment is performed. In the case of the automatic encoder, we proved that the accuracy and predicted value varying per 1,000 EPOCH are linearly changed several times with the increasing value of the variable.

• The Journal of the Korea Contents Association
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• v.21 no.2
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• pp.227-235
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• 2021

The purpose of this study was to investigate the association factors of dental infection control by applying the health belief model in the dental hygienists. This study subject was 142 dental hygienists from 15 to July 5, 2020. Data were analyzed by chi-square test ANOVA, correlation analysis, and multiple regression analysis using SPSS version 23.0. The performance of dental infection control in accordance with the general characteristics of research subjects was high in case when they had educational experiences of infection control, and when they 'always' did medical examinations by interview about infectious diseases(p<0.01). The group of dental hygienists working for dental clinics with less than average 50 patients a day showed the highest rate of wearing a mask and latex gloves as personal protective gears(p<0.05),(p<0.01). When the wearing of protective goggles(face shield) and the frequency of exchanging masks after the outbreak of COVID-19 were more, the performance for infection control was increasing(p<0.05),(p<0.01),(p<0.001). In this study, it is difficult to generalize the results of the study because the research area and the subject are limited by selecting the subjects by convenience extraction, and focusing on the degree of awareness of infection control by dental hygienists, the actual status of infection control in dentistry is carefully illuminated. What you didn't do can be seen as a limitation. Considering the results of this study, the performance of infection control could be increased by removing obstacles and increasing the importance and perceived benefits of infection control of dental hygienists.