• 연구논문집
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• 통권25호
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• pp.47-54
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• 1995

The atomizing characteristics in a spray injected from a twin fluid atomization nozzle have been investigated. The Sauter mean diameters as mean diameter are compared with wavelength calculated from the instability theory. The Sauter mean diameter are measured by the Fraunhofer diffraction theory using the Malvern particle sizer. The wavelength is calculated using the mean relative velocity instead of the exit relative velocity of nozzle. Also shadowgraphy technique is used to visualize atomization. This paper gives a possibility that the mean diameter can be predicted with the wavelength obtained by the simple instability theory.

• Computers and Concrete
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• 제33권1호
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• pp.27-39
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• 2024

In this study, the authors investigate the free vibration behavior of three-phases functionally graded sandwich plates using a novel nth-order shear deformation theory. These plates are composed of a homogeneous core and two face-sheet layers made of different functionally graded materials. This is the novel type of the sandwich structures that can be applied in many fields of mechanical engineering and industrial. The proposed theory only requires four unknown displacement functions, and the transverse displacement does not need to be separated into bending and shear parts, simplifying the theory. One noteworthy feature of the proposed theory is its ability to capture the parabolic distribution of transverse shear strains and stresses throughout the plate's thickness while ensuring zero values on the two free surfaces. By eliminating the need for shear correction factors, the theory further enhances computational efficiency. Equations of motion are established using Hamilton's principle and solved via Navier's solution. The accuracy and efficiency of the proposed theory are verified by comparing results with available solutions. The authors then use the proposed theory to investigate the free vibration characteristics of three-phases functionally graded sandwich plates, considering the effects of parameters such as aspect ratio, side-to-thickness ratio, skin-core-skin thicknesses, and power-law indexes. Through careful analysis of the free vibration behavior of three-phases functionally graded sandwich plates, the work highlighted the significant roles played by individual material ingredients in influencing their frequencies.

• Journal of Information Technology Applications and Management
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• 제27권1호
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• pp.15-47
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• 2020

The purpose of this study is to investigate the effect of prep-entrepreneurs psychological characteristics and entrepreneurial intention. For this purpose, this study established Positive psychological capital and Public self-consciousness as variables of psychological characteristics based on Social Identity Theory and, as factors affecting Positive psychological capital and Public self-consciousness, established Narcissism, Self-compassion and Career ambition as independent variables based on self-affirmation Theory. In order to verify research hypotheses, 358 questionnaires collected from prep-entrepreneurs were used for the empirical analysis. The results of the analysis are as follows. First, narcissism and self-compassion has a positive effect on positive psychological capital. Second, career ambition has a positive effect on public self-consciousness. Third, positive psychological capital and public self-consciousness has a positive effect on entrepreneurial intention. As the outcome of Mediating effect positive psychological capital and public self-consciousness has a Mediating effect on the relationship between narcissism, self-compassion, career ambition and entrepreneurial intention. This study has a meaning in that it confirmed the influential relationship between the prep-entrepreneurs' psychological characteristics and entrepreneurial intentions. In addition, this study suggested its implications, limitations, and future research directions based on the study results.

• 지식경영연구
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• 제21권1호
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• pp.79-98
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• 2020

The majority of research on institutional theory suggests that the new institutional practices presented by national governments and expert groups is a legitimate demand by society, and that the organization is a passive actor that accepts it. However, individual organizations often perform so-called decoupling acts that run their organizations in their own way instead of following the way the system requires, despite the pressures of a strong institutional environment. In this study, the decoupling behavior of these organizations can be varied by the characteristics of the highest decision maker in the organization based on the upper-echelon theory(UET) even if there is no difference in pressure experienced by individual organizations, and their relationship is empirically analyzed among secondary educational institutions that are relatively strongly regulated by the government. According to the analysis of 192 high schools in Korea, the female principal, the younger the principal, and the higher the educational background, the more likely they are to engage in decoupling behavior that are different from the intent and content of government policies. Therefore, from the results of this study, meaningful theoretical and practical implications can be provided for researchers and managers in the field of knowledge management research.

• 한국정보시스템학회지:정보시스템연구
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• 제26권2호
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• pp.43-62
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• 2017

Purpose This study provided empirical support for the model that explain the formation of privacy concerns in the perspective of Information Boundary Theory. This study investigated an integrated model suggesting that privacy concerns are formed by the individual's disposition to value privacy, privacy awareness, awareness of privacy policy, and government legislation. The Information Boundary Theory suggests that the boundaries of information space dependends on the individual's personal characteristics and environmental factors of e-commerce. When receiving a request for personal information from e-commerce websites, an individual assesses the risk depending on the risk-control assessment, the perception of intrusion give rise to privacy concerns. Design/methodology/approach This study empirically tested the hypotheses with the data collected in a survey that included the items measuring the constructs in the model. The survey was aimed at university students. and a causal modeling statistical technique(PLS) is used for data analysis in this research. Findings The results of the survey indicated significant relationships among environmental factors of e-commerce websites, individual's personal privacy characteristics and privacy concerns. Both individual's awareness of institutional privacy assurance on e-commerce and the privacy characteristics affect the risk-control assessment towards information disclosure, which becomes an essential components of privacy concerns.

• Advances in nano research
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• 제9권4호
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• pp.295-307
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• 2020

The vibrational characteristics of Multi-Phase Nanocomposite (MPC) reinforced annular/circular plate under initially stresses are presented using the state-space formulation based on three-dimensional elasticity theory (3D-elasticity theory) and Differential Quadrature Method (DQM). The MPC reinforced annular/circular plate is under initial lateral stress and composed of multilayers with Carbon Nanotubes (CNTs) uniformly dispersed in each layer, but its properties change layer-by-layer along the thickness direction. The State-Space based Differential Quadrature Method (SS-DQM) is presented to examine the frequency behavior of the current structure. Halpin-Tsai equations and fiber micromechanics are used in the hierarchy to predict the bulk material properties of the multi-scale composite. A singular point is investigated for modeling the circular plate. The CNTs are supposed to be randomly oriented and uniformly distributed through the matrix of epoxy resin. Afterward, a parametric study is done to present the effects of various types of sandwich circular/annular plates on frequency characteristics of the MPC reinforced annular/circular plate using 3D-elasticity theory.

• 한국항공우주학회지
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• 제34권3호
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• pp.1-5
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• 2006

자연에 존재하는 새나 곤충들은 양력 및 추력을 발생하기 위하여 평균캠버선의 형상을 변화시킨다. 기존의 비정상 박익 이론들은 주로 강체 플랩핑 에어포일에 관하여 유도되어 왔다. 생체형상가변익의 비정상 공력특성을 파악하기 위하여 변형 가능한 에어포일에 대한 확장된 비정상 박익이론이 필요하다. 생체형상가변익의 비정상 공력특성을 계산하기 위해 Theodorsen의 접근방법을 확장하였다. 에어포일의 평균 캠버선은 다항식으로 나타내었다. 형상 가변익에 작용하는 비정상 공력특성을 순환항 및 비순환항으로 나누어 나타내었다. 본 이론은 플래핑운동을 하는 생체형상가변 에어포일의 비정상 공력해석 및 모핑날개의 공탄성 해석에 적용가능하다.

• 한국정보시스템학회지:정보시스템연구
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• 제30권4호
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• pp.43-69
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• 2021

Purpose Although companies occupied the network market take the advantageous position first and can be successful in securing users over a certain size, it is important to satisfy the customers' demand and prevent the outflow of users toward a new alternative SNS. What is more, there are frequent changes in the flow of users toward new SNSs. Despite these dynamic market circumstances, there is a lack of research to explain the switching behaviors of SNS users. Design/methodology/approach The objective of this study is to explain and verify a specified migration theory(Push-Pull-Mooring model) focused on SNS fatigue in the psychological point of view, as well as reviewing previous studies on functional and technical characteristics of SNSs themselves. Moreover, this study tried to highlight factors affecting users actual SNS switch rather than their switching intention. Findings According to the statistical analysis, the most influenced pull factor to switch SNS was the alternative attractiveness. On the other hand, undesired relationship burden, service innovation and important mooring factors to prevent users' SNS switch. This study has a significant contribution to the theory, which analyzed users' actual SNS switch, and examined SNS users' psychological factors(SNS fatigue), reviewing the characteristics of existing services. To secure more users and to keep them, companies providing social network service need to develop differentiated strategies by analyzing psychological characteristics of various users.

• Steel and Composite Structures
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• 제26권4호
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• pp.421-437
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• 2018

Free vibration analysis of a three-layered microbeam including an elastic micro-core and two piezo-magnetic face-sheets resting on Pasternak's foundation are studied in this paper. Strain gradient theory is used for size-dependent modeling of microbeam. In addition, three-unknown shear and normal deformations theory is employed for description of displacement field. Hamilton's principle is used for derivation of the governing equations of motion in electro-magneto-mechanical loads. Three micro-length-scale parameters based on strain gradient theory are employed for prediction of vibrational characteristics of structure in micro-scale. The results show that increase of three micro-length-scale parameters leads to significant increase of three natural frequencies especially for increase of second micro-length-scale parameter. This result is according to this fact that stiffness of a micro-scale structure is increased with increase of micro-length-scale parameters.

• 대한한의학원전학회지
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• 제23권1호
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• pp.125-128
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• 2010

The visceral manifestation theory in the "Hwangjenaegyeong(黃帝內經)" was constructed by the reference of the study of Confucian classics which main characteristics is the extensive application of the five phase theory. "Image" plays an important role in the thinking of the Chinese ancient people and it is the basis of the construction of the visceral manifestation theory. "Concept of holism" is the main directed thinking of the "Hwangjenaegyeong(黃帝內經)" "Four seasons, five viscera, Yin yang" theory is the core contents of the visceral manifestation theory in the "Hwangjenaegyeong(黃帝內經)".