• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.2
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• pp.249-258
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• 1998

In land mobile communication, very extensive studies on pilot symbol assisted modulation (PSAM) have been made on fading compensation. This paper analyzes the effect of power amplifier nonlinearity on PSA-QAM with maximal ratio combining space diversity. In practical PSAM, information on fading is obtained through interpolation of the pilot symbols. We employed the interpolation filter which could minimize the average power of error and analyzed effects on the system performance of the number of filter taps, period of the pilot symbol frame, and the Doppler frequency. Nonlinear power amplifiers of class AB, B, and C were incorporated in the system models and their AM/AM and AM/PM characteristics were taken into account in the performance analysis. We showed the performance variations according to the types of the nonlinear power amplifiers in the AWGN and Rayleigh fading channels using nonlinear compensation technique, Cartesian Feedback Loop (CFB).

• Journal of Navigation and Port Research
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• v.38 no.5
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• pp.503-509
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• 2014

In this study, a new concept perforated breakwater is proposed, which is having resonant channels. In the channel, perforated plate is installed for dissipating wave energy induced by flow separations. The breakwater has two advantages compared with conventional perforated breakwater having wave chamber with slotted walls. One is easy to control the target wave condition for dissipating wave energy, and the other is having the high structural safety because the structural members are not exposed to impact waves, directly. To evaluate wave reflection characteristics of the proposed breakwater, numerical experiment was carried out by using Galerkin's finite element model based on the linear potential theory. The results indicated that considerable energy dissipation occurs near the resonant period of channel, and wave reflection characteristics are affected by channel shape, location and opening ratio.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7831-7837
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• 2015

In order to understand how various support programs affect the development of traditional performing arts, I used descriptive statistics and multivariate statistics analysis on 267 surveys. I estimated relationship between item-whole by calculating mean and standard deviation. This will help us comprehend effects of the variables. Cronbach alpha coefficient, a measure of internal consistency, exceeded 0.7, indicating that reliability is satisfactory. I have established one main hypothesis and four sub-hypothesis to identify the relationship between support programs and the performing arts more clearly. The result supports that the support programs do have effects on the performing arts. However, there are not enough researches done on this subject, and additional researches are needed in order to systemize relevant theories and the development of performing arts industry.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5412-5419
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• 2011

The need is growing for high-speed spindle because various equipment are becoming more precise, miniaturization and high speed with the development of industries. Air-lubricated dynamic bearings are widely used in the optical lithographic manufacturing of wafers to realize nearly zero friction for the motion of the stage. Air-lubricated dynamic bearing can be used in high-speed, high-precision spindle system and hard disk drive(HDD) because of its advantages such as low frictional loss, low heat generation, averaging effect leading better running accuracy. In the paper, numerical analysis is undertaken to calculate the performance of air-lubricated dynamic bearing with herringbone groove. The static performances of herringbone groove bearings which can be used to support the thrust load are calculated. Electrochemical micro machining($EC{\mu}M$) which is non-contact ultra precision machining method has been developed to fabricate the air-lubricated dynamic bearing and optimum parameters which are inter electrode gap size, concentration of electrolyte, machining time are simulated using numerical analysis program.

• Journal of Digital Convergence
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• v.19 no.10
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• pp.377-382
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• 2021

A fuzzy relation between X and Y as fuzzy subset of X × Y was proposed by Zadeh. Subsequently, several researchers have applied the notion of fuzzy subsets to various branches of mathematics and computer sciences. Murali an Nemitz have studied fuzzy relations connected with fuzzy equivalence relations and fuzzy functions. Ounalli and Jaoua defined a fuzzy difunctional relation on a set. difunctional relations are versatile mathematical tool, which can be used in software design and in database theory. Their work have revealed the usefulness of difunctional relations in program specification and in defining program correctness. The main goal of this paper is to define a fuzzy deterministic relation on a set, characterize the fuzzy deterministic relation as its level subsets and investigate some properties in connection with fuzzy deterministic relation. In particular we prove that a fuzzy relation R is fuzzy deterministic iff R is a fuzzy function.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.8
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• pp.331-338
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• 2021

Metaverse is a compound word of 'meta' and 'universe', which means transcendence and the world. It is a digital world where daily life and economic activities are possible. While the Metaverse is being actively used as an alternative space to enjoy leisure life since COVID-19, not much academic research on Metaverse in Korea has been done yet. Based on the previous research on Metaverse in Korea and overseas we conducted a typology analysis on cultural leisure-based Metaverse and a study on its key features. Considering the current situation in which the Metaverse era is blooming we also investigated the development trends of the Metaverse and related technologies at home and abroad. We also presented the direction of advancement of the cultural leisure-based Metaverse. This study differentiates itself from previous domestic and foreign studies by discovering and analyzing theoretical models, frameworks and features in terms of society, collaboration, and leisure use through case studies. It is meaningful that this research presents directions on further Metaverse research that reflect the current information technology (IT) and changes in life.

• Plant Journal
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• v.15 no.1
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• pp.25-30
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• 2019

In this study, by varying flow patterns, which is one of the hydraulic factors of FAC, a strategy to reduce pipe wall thinning by mass transfer has been investigated. A similarity between heat transfer and mass transfer was verified via theoretical analysis, and local convective heat transfer coefficients were analyzed using a commercial numerical analysis program. When ribs were installed inside and outside of the internal surface in the straight section of the pipe, the maximum local heat transfer coefficient was shown to decrease substantially by up to 24.9% compared to the basic flow depending on the position and shape of ribs. If a guide vein was inserted in the pipe elbow, the maximum local heat transfer coefficient decreased by up to 26.7% compared to the basic flow depending on the internal surface area of the pipe by the guide vein.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.447-454
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• 2019

The purpose of this study aims to be used as base data of a policy which forms university students' appropriate behavior for the prevention of infection by analyzing some university students' prevention awareness of new type of infection. A self-administered questionnaire survey about students' seriousness, sensitivity, self-efficacy, and prevention behavior intent of new infection, was conducted in an university located in Gyeonbuk from April. 30th to May. 11th, 2018. Analyzing factors which affect the prevention behavior intent of infection with controlled general factor and health behavior, the prevention behavior intent was increased by ${\beta}=.125$ as seriousness increases and ${\beta}=.709$ as self-efficacy increases in Model 2, final model. However, sensitivity has no significant effect on the prevention behavior intent. Originally sensitivity has to be a significant factor regarding to the prevention behavior intent of new infection. But the result that sensitivity has no influence at all, shows that the students are insensitive to new diseases as they don't fear or sense danger of new infection. Therefore, a disease control policy which helps to increase sensitivity has to be established.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5D
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• pp.597-607
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• 2008

ATIS(Advanced Traffic Information System) provide valuable information as the travel time and traffic congestion, detour, traffic accident information to drivers, so it is being in the spotlight. But so far, the study on the consumer satisfaction with providing traffic information is incomplete. So, this study run a Canonical discriminant analysis and a Canonical correlation analysis by a QuantificationIItheory based on a Traffic Information Satisfaction image data through questionnaires, and found out the factors with influence on the consumer satisfaction. And this study definitely found out the correlation between consumer's recognition and traffic information satisfaction through understanding the change on the recognition about traffic information satisfaction by a QuantificationItheory. Finally, this study found out the change on the sensibility recognition of drivers by running the principal component anlysis, developed the traffic information satisfaction evaluation model considering the change on the recognition by using the structural equation model.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.4
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• pp.185-208
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• 2023

In this study, a research model was designed and verified in order to determine whether the communication styles of public library managers affect employees' empowerment, job satisfaction, and life satisfaction. A survey was conducted among employees of four public libraries in the Gyeonggi region and 24 libraries in Seoul, and 229 valid responses were analyzed. The analysis revealed that authoritative communication style influenced employees' job satisfaction, while social communication style influenced their empowerment. Additionally, employees' empowerment impacted their job satisfaction, which in turn affected their life satisfaction. This implies that job satisfaction and life satisfaction of the employees can be achieved after communication and empowerment were well established within the organization. This study is meaningful in suggesting an effective management direction for strengthening the essence and foundation of public libraries by examining the theoretical significance and implications of the research result. This study also suggested that in the future, another research should be conducted based on a variety of characteristics by integrating the different communication styles of researchers.