• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.1897-1907
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• 1991

An analysis is presented for the primary resonance of a clamped-hinged beam, which occurs when the frequency of excitation is near one of the natural frequencies, .omega.$_{n}$. Three mode interactions, .omega.$_{2}$=3.omega.$_{1}$, and .omega.$_{3}$=.omega.$_{1}$+2.omega.$_{2}$, are considered and their influence on the response is studied. The case of two mode interaction, .omega.$_{2}$=3.omega.$_{1}$, is also considered in order to compare it with the case of three mode interactions. The straight beam experiencing mid-plane stretching is governed by a nonlinear partial differential equation. By using Galerkin's method the governing equation is reduced to a system of nonautonomous nonlinear ordinary differential equations. The method of multiple scales is applied to obtain steady-state responses of the system. Results of numerical investions show that there exists no significant difference between both modal interactions.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.1
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• pp.27-35
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• 1986

The optical wave interactions in a sinusoidally corrugated dielectric waveguide are analyzed for the oblique incidence case. The coupled mode equations which govern the interactions are derived by the singular perturbation method for the TE-TE mode coupling. The results are compared with those of normal mode analysis by Wagatsuma et al. and total field analysis by Stegeman et al. Phase mismatching effects on the diffraction efficiency are also investigated.

• Journal of the Korean Society of Safety
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• v.33 no.1
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• pp.81-87
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• 2018

The seismic response, the natural frequencies and the mode shapes of an offshore wind turbine with twisted tripod substructure subject to various pile-ground interactions are discussed in this paper. The acceleration responses of the tower head by four historical earthquakes are presented as the seismic response, while the other loads are assumed as ambient loads. For the pile-ground interactions, the fixed, linear and nonlinear models are employed to simulate the interactions and the p-y, t-z and Q-z curves are utilized for the linear and nonlinear models. The curves are designed for stiff, medium and soft clays, and thus, the seven types of the pile-ground interactions are used to compare the seismic response, the acceleration of the tower head. The mode shapes are similar to each other for all types of pile-ground interactions. The natural frequencies, however, are almost same for the three clay types of the linear model, while the natural frequency of the fixed support model is quite different from that of the linear interaction model. The wind turbine with the fixed support model has the biggest magnitude of acceleration. In addition, the nonlinear model is more sensitive to the stiffness of clay than the linear pile-ground interaction model.

• Communications of the Korean Mathematical Society
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• v.15 no.1
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• pp.155-172
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• 2000

Mode interactions at Unstable fluid interfaces induced by a shock wave (Richtmyer-Meshkov Instability) are studied both analytically and numerically. The analytical approach is based on a potential flow model with source singularities in incompressible fluids of infinite density ratio. The potential flow model shows that a single bubble has a decaying growth rates at late time and an asymptotic constant radius. Bubble interactions, bubbles of different radii propagates with different velocities and the leading bubbles grow in size at the expense of their neighboring bubbles, are predicted by the potential flow model. This phenomenon is validated by full numerical simulations of the Richtmyer-Meshkov instability in compressible fluids for initial multi-frequency perturbations on the unstable interface.

• Clinical and Experimental Pediatrics
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• v.65 no.5
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• pp.239-249
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• 2022

Cells survive and proliferate through complex interactions among diverse molecules across multiomics layers. Conventional experimental approaches for identifying these interactions have built a firm foundation for molecular biology, but their scalability is gradually becoming inadequate compared to the rapid accumulation of multiomics data measured by high-throughput technologies. Therefore, the need for data-driven computational modeling of interactions within cells has been highlighted in recent years. The complexity of multiomics interactions is primarily due to their nonlinearity. That is, their accurate modeling requires intricate conditional dependencies, synergies, or antagonisms between considered genes or proteins, which retard experimental validations. Artificial intelligence (AI) technologies, including deep learning models, are optimal choices for handling complex nonlinear relationships between features that are scalable and produce large amounts of data. Thus, they have great potential for modeling multiomics interactions. Although there exist many AI-driven models for computational biology applications, relatively few explicitly incorporate the prior knowledge within model architectures or training procedures. Such guidance of models by domain knowledge will greatly reduce the amount of data needed to train models and constrain their vast expressive powers to focus on the biologically relevant space. Therefore, it can enhance a model's interpretability, reduce spurious interactions, and prove its validity and utility. Thus, to facilitate further development of knowledge-guided AI technologies for the modeling of multiomics interactions, here we review representative bioinformatics applications of deep learning models for multiomics interactions developed to date by categorizing them by guidance mode.

• Journal of the Korean Magnetic Resonance Society
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• v.22 no.4
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• pp.76-81
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• 2018

Investigation of the protein-protein interaction mode at atomic resolution is essential for understanding on the underlying functional mechanisms of proteins as well as for discovering druggable compounds blocking deleteriou interprotein interactions. Solution NMR spectroscopy provides accurate and precise information on intermolecular interactions even for weak and transient interactions, and it is also markedly useful for examining the change in the conformation and dynamics of target proteins upon binding events. In this mini-review, we comprehensively describe three unique and powerful methods of solution NMR spectroscopy, paramagnetic relaxation enhancement (PRE), pseudo-contact shift (PCS), and residual dipolar coupling (RDC), for the study on protein-protein interactions.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.32.2-32.2
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• 2009

We examine cyclotron resonant interactions of radiation belt electrons with VLF chorus, plasmaspheric ELF hiss and electromagnetic ion cyclotron (EMIC) waves. Bounce-averaged diffusion rates depend on wave mode, equatorial pitch-angle, electron energy and L-shell. As well, diffusion rates can be sensitive to the latitudinal distributions of particle density and wave power. For different configurations of the plasmasphere, we calculate electron precipitation loss timescales due to combined scattering by VLF chorus, ELF hiss and EMIC waves.

• Geomechanics and Engineering
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• v.29 no.6
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• pp.627-643
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• 2022

Water-rock interactions have a significant influence on the mechanical behavior of rocks. In this study, uniaxial compression and tension tests on different water-treated sandstone samples were conducted. Acoustic emission (AE) monitoring and micro-pore structure detection were carried out. Water-rock interactions and their effects on rock mechanical behavior were discussed. The results indicate that water content significantly weakens rock mechanical strength. The sensitivity of the mechanical parameters to water treatment, from high to low, are Poisson ratio (𝜇), uniaxial tensile strength (UTS), uniaxial compressive strength (UCS), elastic modulus (E), and peak strain (𝜀). After water treatment, AE activities and the shear crack percentage are reduced, the angles between macro fractures and loading direction are minimized, the dynamic phenomenon during loading is weakened, and the failure mode changes from a mixed tensile-shear type to a tensile one. Due to the softening, lubrication, and water wedge effects in water-rock interactions, water content increases pore size, promotes crack development, and weakens micro-pore structures. Further damage of rocks in fractured and caved zones due to the water-rock interactions leads to an extra load on the adjoining coal and rock masses, which will increase the risk of dynamic disasters.

• Steel and Composite Structures
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• v.2 no.3
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• pp.223-236
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• 2002

An analytical procedure based on the transfer matrix method to estimate not only the natural frequencies but also vibration mode shapes of the thin-walled members composed of interconnected cylindrical shell panels is presented. The transfer matrix is derived from the differential equations for the cylindrical shell panels. The point matrix relating the state vectors between consecutive shell panels are used to allow the transfer procedures over the cross section of the members. As a result, the interactions between the shell panels of the cross sections of the members can be considered. Although the transfer matrix method is naturally a solution procedure for the one-dimensional problems, this method is well applied to thin-walled members by introducing the trigonometric series into the governing equations of the problem. The natural frequencies and vibration mode shapes of the thin-walled members composed of number of interconnected cylindrical shell panels are observed in this analysis. In addition, the effects of the number of shell panels on the natural frequencies and vibration mode shapes are also examined.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1391-1395
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• 2006

In non-contact mode atomic force microscopy, the response of a resonating tip is used to measure the nanoscale topography and other properties of a sample surface. However, the tip-surface interactions can affect the tip response and destabilize the non-contact mode control. Especially it is difficult to obtain a good scanned image of high adhesion surfaces such as polymers using conventional hard NCHR tip and non-contact mode control. In this study, experimental investigation is made on the non-contact mode imaging and we report the microcantilever having low stiffness (OMCL) is useful to measure the properties of samples such as elasticity. In addition, we proved that it was adequate to use low stiffness microcantilever to obtain a good scanned image in AFM for the soft and high adhesion sample.