• Journal of the Korean Society for Aviation and Aeronautics
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• v.27 no.4
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• pp.37-43
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• 2019

Obstacle limitation surfaces are imaginary space surfaces that must be clear of obstacles for the aircraft to safely take off and land on the aerodrome. These surfaces are closely related to the safety of the VFR aircraft, which require a pilot to be able to see outside the cockpit, to control the aircraft's altitude, navigate, and avoid obstacles and other aircraft. The Republic of Korea, which has a lot of restrictions on the use of airspace, cannot provide a rich operating environment for VFR aircraft. Under these circumstances, safer operation will not be guaranteed if additional factors that directly or indirectly affect existing VFR routes, such as drone delivery services. This study analyzes and models the track distribution of each VFR section based on radar track data around a specific airport. Through this study, we estimate the three-dimensional space for VFR aircraft and provide the data for future research such as airspace analysis of VFR corridors and correlation with obstacle limitation surfaces.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.29-30
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• 2012

In this paper, a performance of bi-directional DC/DC converter using PFM control at whole load range is analyzed. A bi-directional DC/DC converter using PFM control in this paper can be soft switching operation with LC series resonant circuit. It's difficult to expect a high efficiency at whole load range in general resonant converter because of limitation of soft switching area. Therefore converter used in this paper has a variable frequency PFM control to overcome a limitation of soft switching area and it makes a high efficiency at whole load range by implementing a soft switching at light load area of restricted soft switching. The high efficiency at whole load range is verified by simulation and experimental result.

• Journal of Korean Society of Rural Planning
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• v.22 no.2
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• pp.45-55
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• 2016

From 1970, the concept of ecotourism is introduced, lots of studies in ecotourism appeared. Review these studies are necessary for future ecotourism studies. Some review studies on ecotourism are existed. However, these approach also limitation of subjectivities and some sorts of papers has not been reviewed. This study use keyword network analysis which is used as big data analysis to overcome the limitation. Foreign 2455 studies and domestic 163 studies which have ecotoursim in keywords, are analyzed for reviewing. As a result, 3 cluster('Sustainable tourism development', 'Ecological conservation', 'Ecotourist analysis' appeared, in ecotourism studies. In addition, this cluster has deep relationship with region. 'Sustainable tourism development' is related to Eurasia, Australia, Europe. 'Ecological conservation' is related to Africa. 'Ecotourism analysis' is related to North America. Especially 'Resident participation', 'Stakeholder' are appeared many times in Asia region. These results show that ecotourism studies are interpreted in regional contexts. It means that although only one word 'ecotourism' is used in different contexts, regional approach are needed for exact use. In Korea, the keywords are focused on ecotourists and developments. As Korea has lots of ecotour village, resident participation studies have to be supplemented.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.2
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• pp.147-160
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• 2019

Compared with the research on consumer engagement in brand community, the research on consumer engagement in brand public has been relatively less. This research aimed at exploring how brand public characteristics such as information variety, various communications and no limitation in expressing self affect the brand public engagement. 274 questionnaires answered by Chinese consumers are used to conduct analysis. Principal component analysis is used to test the reliability and validity of each construct, and structural equation model is used to test hypotheses. The study finds the positive effects of information variety on information benefits, those of various communications on social benefits, and also positive roles of no limitation in expressing self to brand-related self-expression motivation. And each of the information benefits, social benefits and brand-related self-expression motivation is proved to positively affect brand public engagement. The study implies that marketers should give attention to characteristics of brand public, and provide the ways by which members of brand public engage the brand. Additionally, marketers should pay more attention to both direct and indirect engagement activities of consumers toward brand public in social media to better understand their target consumers.

• Women's Health Nursing
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• v.15 no.2
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• pp.99-107
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• 2009

Purpose: This study was aimed to identify the factors related to the health related quality of life (HRQoL) in elderly women. Method: This study used data from cross-sectional surveys conducted for the 2005 National Health and Nutrition Survey, which was performed by using a face to face interview method. Data was analyzed by ANOVA, t-test, logistic regression and multiple regression using the SPSS program. Demographic characteristics, subject health state, activity limitation, K-ADL, K-IADL, EQ-5D were included in the study instruments. Result: The mean HRQoL index in the subjects was 0.68 $\pm$ 0.25. The significant predictors of the HRQoL were health status, activity limitation, activities of daily living (ADL), instrumental activities of daily living (IADL) and income. The factors accounted for 41.0% of variance in the health related quality of life of female elderly. Conclusion: These results may contribute to development of nursing strategy to improve health related quality of life. The health related quality of life program for the elderly should be planned based on results of the study.

• Nuclear Engineering and Technology
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• v.34 no.4
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• pp.396-405
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• 2002

An experimental study on counter-current flow limitation phenomena in narrow annular passages was carried out The gap sizes tested were 1, 2 and 3 mm. This is very small compared with the outer diameter of the annular passage, 500 mm. It was visually observed that a CCFL might occur in some part of the periphery while the other part is remained in a counter current flow pattern. That is, non-uniform behaviour of fluids due 4o a 2-dimensional effect appear in a large diameter facility. Because of this non-uniformity, a CCFL is defined in the present work as the situation where net water accumulation is sustained. That is, some amount of water should not be allowed to penetrate the gap and accumulate over the gap at CCFL criterion. The measured data are presented in the form of Wallis＇type correlation with characteristic length of gap size. It was found that the present correlation is in good agreement with other empirical correlation based on measurements whose test section diameter is close and the gap size is much larger than that of the present test section.

• Journal of the Korea Society of Computer and Information
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• v.24 no.8
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• pp.59-66
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• 2019

As the monetary value of cryptocurrency increases, the security measures for cryptocurrency becomes more important. A limitation of the existing cryptocurrency exchanges is their vulnerability to threats of hacking due to their centralized manner of management. In order to overcome such limitation, blockchain technology is increasingly adopted. The blockchain technology enables decentralization and Peer-to-Peer(P2P) transactions, in which blocks of information are linked in chain topology, and each node participating in the blockchain shares a distributed ledger. In this paper, we propose and implement a mobile electronic wallet that can safely store, send and receive cryptocurrencies. The proposed mobile cryptocurrency wallet connects to the network only when the wallet actively is used. Wallet owner manages his or her private key offline, which is advantageous in terms of security. JavaScript based wallet apps were implemented to respectively run on Android and iOS mobile phones. I demonstrate the process of transferring Ethereum cryptocurrency from an account to another account through Ropsten, a test net for Ethereum. Hardware wallets, such as Ledger Nano S, provide a slightly higher level of security, yet have the disadvantages of added burden of carrying additional physical devices and high costs (about 80$).

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.558-566
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• 2018

The objective of the study was to determine nutrition regime and limitation in the Boryeng Reservoir where there's a water tunnel between Geum River and the reservoir. Evaluation was conducted through in situ algal bioassay experiments (in situ ABEs) using the cubitainer setting in the reservoirs. For in situ ABEs, we compared and analyzed variations in chlorophyll-a (CHL-a) and phosphorus concentrations in Boryeong Reservoir before and after the water tunnel construction. We then analyzed the nutrient effects on the reservoir. Analysis for nitrogen and phosphorus was done in the three locations of the reservoir and two locations of the ABEs. The in situ ABEs results showed that phosphorous and Nitrogen, the primary limiting nutrient regulating the algal biomass was not limited in the system. The treatments of phosphorus or simultaneous treatments of N+P showed greater algal growth than in the control of nitrate-treatments, indicating a phosphorus deficiency on the phytoplankton growth in the system. The water from the Geum River had 5 times higher total phosphorus (TP) than the water in the reservoir. Efficient management is required as pumping of the river water from Geum River may accelerate the eutrophication of the reservoir.

• Investigative Magnetic Resonance Imaging
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• v.23 no.2
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• pp.167-171
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• 2019

$M\ddot{o}bius$ syndrome is a rare congenital condition, characterized by abducens and facial nerve palsy, resulting in limitation of lateral gaze movement and facial diplegia. However, to our knowledge, there have been few studies on evaluation of cranial nerves, on MR imaging in $M\ddot{o}bius$ syndrome. Herein, we describe a rare case of $M\ddot{o}bius$ syndrome representing limitation of lateral gaze, and weakness of facial expression, since the neonatal period. In this case, high-resolution MR imaging played a key role in diagnosing $M\ddot{o}bius$ syndrome, by direct visualization of corresponding cranial nerves abnormalities.

• PNF and Movement
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• v.11 no.1
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• pp.79-88
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• 2013

Purpose : Currently, ICF to describe the functions and disability in the world has been used as a universal language. ICF tools based on ICF, the rehabilitation management of clients have been developed to be efficient. This study was designed to describe clinical decision for functional goal of clients to used ICF tools. Methods : In the following the utilization of all developed ICF tools will be described within a case example of a 53-year-old women, suffering from cerebellum disorder. As problems in the subject's functional activities was difficulties in changes sitting postures, standing postures and maintaining standing postures. Activity limitation was determined change sitting, standing posture as a goal through discussion with the patient. Results : After setting the identified problems as the purpose of intervention through the assessment, we find out the outcomes using the ICF evaluation display. Consequently, with functional activities limitation that discovered from assessment(categorical profile, assessment sheet), sitting postures to standing postures and maintaining standing postures were improved. Conclusion : This study was showed ICF tools based on Rehab-cycle for the patient's functional goals clinical practice. The future study, the ICF in clinical practical tools for effective use will require more attempt.