• Proceedings of the KIEE Conference
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• 1995.11a
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• pp.195-198
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• 1995

Most of the theorems of nonlinear stability is based on the Lyapunov stability theory. The Lyapunov function method is the most well-known and provides precise and rigorous theoretical backgrounds. However, tile conventional approach to direct stability analysis has been performed without taking account of damping effects. For accurate stability analysis of nonlinear systems, it is required to consider the damping effects. This paper presents a new method to derive a group of Lyapunov functions to reflect the damping effects by considering the integral relationships of the system governing equations. This method tan be utilized as a powerful tool to determine the region of attraction.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.3
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• pp.144-153
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• 1996

The magnetic levitation system has many advantages, such as little friction, no lubrication, no noise and so on. For this reason, the magnetic levitation system is utilized in the magnetic bearing of high-speed rotor. The method to obtain magnetic force is both the repulsive suspension method and the attraction suspension method need a stabilizing controller because it is a unstable system in natural. This paper presents the design of robust stabilizing servo controller in spite of being the model uncertainties in the magnetic levitation system by $\textit{H}_{\infty}$ control theory using the free parameter. And we investigated the validity of a designed controller through results of the simulation and the actual experiment.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.231-236
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• 2013

Some cytotoxicity studies for the interpretation of the interaction between nanoparticles and cells are non-mechanistic and time-consuming. Therefore, non-biological screening methods, which are faster and simpler than in-vivo and in-vitro methods, are required as alternatives to current cytotoxicity tests. Here, we proposed a simple screening method for the analysis of the interaction between several AgNPs (bare-, citrate-, and polyvinylpyrrolidone-coating) and dye-containing vesicles acting as a biomimetic cell-membrane. The interaction between AgNPs and vesicles could be evaluated readily by UV-vis spectra. Absorbance deviation in UV-vis spectra revealed a large attraction between neighboring particles and vesicles. This was confirmed by (Derjagin, Landau, Verwey, and Overbeek) theory and DMF (dark-field microscopy) analysis. This proposed method might be useful for analyzing the cytotoxicity of nanoparticles with cell-membranes instead of in vitro or in vivo cytotoxicity tests.

• Journal of Digital Convergence
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• v.15 no.10
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• pp.93-101
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• 2017

This study investigate the effect of each type of search volume on the number of Facebook fans and the number of tourists. According to the hierarchy effect model, the effect of communication appears to be the sequentiality of cognition-attitude-behavior. Applying this theory, this study predicted that when consumers who have higher involvement and knowledge on specific cities through search behavior, they will be more active in information search through Facebook fan page subscription and will lead to direct tourism behavior. To verify the prediction, we examined the influences among search volume of Seoul shown in Google Trend, the number of fans of official facebook page named 'Seoul Korea', and the number of foreign tourists. As a result, the type of search keyword was divided into four categories: tourism attraction keyword, natural environment keyword, symbolic keyword, and accessibility keyword. The regression analysis showed that tourism attraction keyword and symbolic keyword have influence on Facebook fanpage 'Like'. In addition, facebook fanpage fan size have mediation effect between search volume and number of tourists. All in all, it would be useful to appeal to foreign tourists with a message that emphasizes tourism attraction and Korea-related contents.

• Korean Journal of Culture and Social Issue
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• v.22 no.2
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• pp.203-222
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• 2016

Previous research has demonstrated that imagined contact is useful to reducing prejudice against minorities (e.g. Turner & Crisp, 2010). In this research, we investigated whether imagined contact increases attraction to physically unattractive women, and whether this effect is moderated by perceiver's physical attractiveness and appearance orientation in romantic relationships. Single male participants (n = 98) responded to items assessing their physical attractiveness and appearance orientation, and then were randomly assigned to one of the two conditions. In the imagined contact condition, participants were told to imagine communicating with a physically unattractive woman and come up with some interesting things about her. In the control condition, participants were told to simply imagine a physically unattractive woman. Next, participants saw a picture of a physically unattractive woman and rated her likeability, perceived attractiveness, and willingness to ask her out, which were averaged to form the composite measure of attraction. We found a significant main effect of imagined contact, as expected. This main effect was moderated by appearance orientation, but not by perceivers' physical attractiveness. The effect of imagined contact was significant among those low in appearance orientation, but not among those high in appearance orientation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.5988-5994
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• 2014

This study examined the effects of dubbing on the ticket sales of foreign animation movies put on the screen in Korea in the context of 'Skopos Theory'. The ticket power of animation increased when dubbing was chosen as the translation strategy. Moreover, the effects were greater when the animation was in the peak seasons, classified as non-restricted, and made in non-US countries. The ticket power was also found to be greater when celebrities joined in the dubbing. This finding was consistent with the 'Skopos Theory', which implied that dubbing is superior to captioning for audience understanding and audience attraction. This study confirmed empirically the positive effects of dubbing on the performance of foreign animation movies, which is the contribution to the literature that has been limited on case studies. These results also suggest that a dubbing strategy should be consistent with its target audience.

• Journal of the Mineralogical Society of Korea
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• v.28 no.2
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• pp.95-108
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• 2015

Nano-sized iron colloids are formed as acid mine drainage is exposed to surface environments and is introduced into surrounding water bodies. These iron nanomaterials invoke aesthetic contamination as well as adverse effects on aqueous ecosystems. In order to control them, the characteristics of their behaviour should be understood first, but the cumulative research outputs up to now are much less than the expected. Using zero-valent iron (ZVI) and magnetite, this study aims to investigate the behaviour of iron nanomaterials according to the change in the composition and pH of background electrolyte and the concentration of natural organic matter (NOM). The size and surface zeta potential of iron nanomaterials were measured using dynamic light scattering. Characteristic behaviour, such as aggregation and dispersion was compared each other based on the DLVO (Derjaguin, Landau, Verwey, and Overbeek) theory. Whereas iron nanomaterials showed a strong tendency of aggregation at the pH near point of zero charge (PZC) due to electrostatic attraction between particles, their dispersions became dominant at the pH which was higher or lower than PZC. In addition, the behaviour of iron nanomaterials was likely to be more significantly influenced by cations than anions in the electrolyte solutions. Particularly, it was observed that divalent cation influenced more effectively than monovalent cation in electrostatic attraction and repulsion between particles. It was also confirmed that the NOM enhanced the dispersion nanomaterials with increasing the negative charge of nanomaterials by coating on their surface. Under identical conditions, ZVI aggregated more easily than magnetite, and which would be attributed to the lower stability and larger reactivity of ZVI.

• The Korean Journal of Rheology
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• v.11 no.2
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• pp.128-134
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• 1999

Rheological characterization was examined for two different types of magenetic particle (rod-like $\gamma$-$Fe_{2}O_{3}$, $CrO_2$ )suspension in this study. The measured suspension viscosity (viscosity vs. concentration or shear rate) is used to obtain the dependence of viscous energy dissipation on the microstructural states of magnetic particle dispersions as well as the microstructural shape effects which are related to magnetic particle orientation. The empirical formulas from mean field theory and the Mooney equation are used to relate suspension viscosity to particle concentration. Intrinsic viscosities of these two different types of rod-like magnetic particle suspensions are found to exceed the prediction of hydrodynamic theory for dilute suspensions and support the existence of flocs containing significant amounts of immobilized suspending medium due to native attraction forces among particles in the microstructures.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.121-129
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• 2009

This research tries to interpret Montage der Assoziation shown in animations. Eisenstein's 'Montage' is "Montage der Assoziation" where a variety of Montage pieces are combined, symbolizing one aggregate image. Though influenced by Russian Formalist Film Theory and Kuleshov, Pudivkin and Rudolf Amheim, by contraries, he recognized Montage as an issue between an artist and the audience and an anti-representation apparatus. Especially, he developed the mind action issue previously advocated by Eikhenbaum and deemed the audience's role an essential part in completing a film. Montage expression implied in Eisenstein's theory can be regarded as attraction, collision, and dynamic and intellectual Montage. However, with an in-depth approach, Montage der Assoziation can be interpreted by repetitive, relative and juxtaposed analysis. The reason is that animation Montage is a visual action which takes place in a row among scenes and in the frame. This research addresses communications with the audience which are attained by Montage der Assoziation. In other words, this research makes an in-depth access to how Montage der Assoziation appears and communicates with the audience in an animation work.

• Journal of Internet Computing and Services
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• v.18 no.5
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• pp.95-102
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• 2017

With the development and popularization of Internet, the competition of SNS market is now getting fiercer and fiercer. SNS service providers need to keep updating their service to sustain their customers' continuance use. However, due to the homogenization of functions and services from different applications provided by different developers, there comes a new phenomenon that users shift from one SNS to another SNS. In line with this, the current study aims to explore factors affecting switching intention among SNS users by applying migration theory which explains people's migration behavior from one place to another. Findings from surveys of Korean and Chinese college students suggest that there was a difference of factors influencing switching intention among the two countries. For Korean college students, alternative attraction was the strongest factor leading to SNS switching intention. On the other hand, peer pressure was the strongest factor leading to SNS switching intention among Chinese college students.