• Journal of Advanced Marine Engineering and Technology
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• v.26 no.6
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• pp.646-652
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• 2002

The influence of reciprocating frequency and radius on heat transfer in the roughened rectangular channel is experimentally investigated. The aspect ratio (width/height) of the duct is 2.33 and the rib height is one fifteenth of the duct height. And the ratio of rib-to-rib distance to rib height is 10. The discrete ribs were periodically attached to the button wall of the duct with a parallel orientation. The parametric test matrix involves Reynolds number, reciprocating, and reciprocating radius, in the ranges, 1,000∼6,000, 1.7∼2.5 HB and 7∼15cm, respectively. The combined effects of reciprocating frequency and reciprocating radius have considerable influence on the heat transfer due to the modified vortex flow structure.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.12
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• pp.1044-1050
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• 2001

This paper presents firstly the method of Euler angle matching designing the transfer alignment using the attitude matching. In this method, the observation directly uses Euler angle difference between MINS and SINS so it needs to describe the rotation vector error to the Euler angle error. The rotation vector error related to the Euler angle error is derive from the direction cosine matrix error equation. The feasibility of the Kalman filter designed for the transfer alignment by Euler angle matching is analyzed by the alignment error results with respect to the roll angle the pitch angle, and the yaw angle matching.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.2
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• pp.178-184
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• 2002

This paper deals with the transfer alignment problem of SDINS(StrapDown Inertial Navigation System) subjected to roll and pitch motions of the ship. In order to reduce alignment errors induced by ship body flexure, a linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonlinear measurement equation with respect to the dominant y axis component and defining the flexure state of random constant type. And then a robust state estimation scheme is introduced to account for modeling uncertainty of the flexure. By interpreting the simulation results and comparing with the velocity and DCM(Direction Cosine Matrix) partial matching method, it is shown that the proposed method is effective enough to improve the azimuth alignment performance.

• Journal of electromagnetic engineering and science
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• v.16 no.2
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• pp.126-133
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• 2016

Wireless power transfer (WPT) efficiencies for multiple-input multiple-output (MIMO) systems are formulated with a goal of achieving their maximums using Z matrices. The maximum efficiencies for any arbitrarily given configurations are obtained using optimum loads, which can be determined numerically through adequate optimization procedures in general. For some simpler special cases (single-input single-output, single-input multiple-output, and multiple-input single-output) of the MIMO systems, the efficiencies and optimum loads to maximize them can be obtained using closed-form expressions. These closed-form solutions give us more physical insight into the given WPT problem. These efficiencies are evaluated theoretically based on the presented formulation and also verified with comparisons with circuit- and EM-simulation results. They are shown to lead to a good agreement. This work may be useful for construction of the wireless Internet of Things, especially employed with energy autonomy.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.52.2-52.2
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• 2018

The shape of a galaxy's spectral energy distribution ranging from ultraviolet (UV) to infrared (IR) wavelengths provides crucial information about the underlying stellar populations, metal contents, and star-formation history. Therefore, analysis of the SED is the main means through which astronomers study distant galaxies. However, interstellar dust absorbs and scatters UV and optical light, re-emitting the absorbed energy in the mid-IR and Far-IR. I present the updated 3D Monte-Carlo radaitive transfer code MoCafe to compute the radiative transfer of stellar, dust emission through a dusty medium. The code calculates the emission expected from dust not only in pure thermal equilibrium state but also in non-thermal equilibrium state. The stochastic heating of very small dust grains and/or PAHs is calculated by solving the transition probability matrix equation between different vibrational, internal energy states. The calculation of stochastic heating is computationally expensive. A pilot study of radiative transfer models of SEDs in clumpy (turbulent), galactic environments, which has been successfully used to understand the Calzetti attenuation curves in Seon & Draine (2016), is also presented.

• Food Science of Animal Resources
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• v.28 no.3
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• pp.312-318
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• 2008

The objective of this study was to investigate the changes in ice dendrite size during freezing process in gelatin matrix as a model food system in order to provide mathematical relation between freezing condition and ice dendrite size. Gelatin gel as a model matrix was frozen in unidirectional Neumann's type of heat transfer. The thermograms' analysis allowed to determine the freezing temperature of the sample, the position of the freezing front versus time, and thus, freezing front rate. The morphology of ice dendrites was observed by scanning electron microscopy after freeze-drying. We observed that the means size of ice dendrite increased with the distance to the cooling plate; however, it decreased with the cooling rate and the cooling temperature. In addition, the shorter durations of the freeze-drying process was shorter decreeing the decreased the freezing front rate, resulted in their resulting in a larger pore size of the ice dendrite pores for the sublimation channel of that operate as water vapor sublimation channels. From these results, we could derive a linear regression as an empirical mathematical model equation between the ice dendrite size and the inverse of freezing front rate.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.2
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• pp.234-240
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• 2014

In this paper, the interface matrix of honeycomb composite panel has been derived by the governing equation of a honeycomb sandwich panel. The interface matrix of honeycomb panel is added to the previously developed transfer matrix method, thus analysis of the multi-layered insulation composite panel with honeycomb is accomplished. Furthermore, predictions of sound transmission loss(STL) for the ship's insulation panel with honeycomb and mineral wool are presented. The insulation performance of the honeycomb used for skin of the ship's insulation panel is better than that of 0.35 mm steel panel by 2dB, approximately. Although honeycomb panel has inefficient insulation performance beside steel panel, honeycomb panel achieve improvements in the performance of weight reduction. The surface density of the panel with honeycomb is rather than with steel by $5.2kg/m^2$. It is decrease in weight by 31.7 %.

• Journal of Biomedical Engineering Research
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• v.40 no.1
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• pp.1-6
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• 2019

Human mesenchymal stem cells (hMSC) are multipotent stromal cells that have great potential to differentiate into a variety of cell types such as osteocytes, chondrocytes, and myocytes. Although there have been many studies on their clinical availability, little is known about how intracellular signals can be modulated by topographic features of the extracellular matrix (ECM). In this study, we investigated whether and how microwavy-patterned extracellular matrix (ECM) could affect the signaling activity of focal adhesion kinase (FAK), a key cellular adhesion protein. The fluorescence resonance energy transfer (FRET)-based FAK biosensor-transfected cells are incubated on microwavy-patterned surfaces and then platelet derived growth factor (PDGF) are treated to trigger FAK signals, followed by monitoring through live-cell FRET imaging in real time. As a result, we report that PDGF-induced FAK was highly activated in cells cultured on microwavy-patterned surface with L or M type, while inhibited by H type-patterned surface. In further studies, PDGF-induced FAK signals are regulated by functional support of actin filaments, microtubules, myosin-related proteins, suggesting that PDGF-induced FAK signals in hMSC upon microwavy surfaces are dependent on cytoskeleton (CSK)-actomyosin networks. Thus, our findings not only provide new insight on molecular mechanisms on how FAK signals can be regulated by distinct topographical cues of the ECM, but also may offer advantages in potential applications for regenerative medicine and tissue engineering.

• Structural Engineering and Mechanics
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• v.62 no.6
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• pp.759-769
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• 2017

The effect of central axial load on natural frequencies of various thin-walled beams, are investigated by some researchers using different methods such as finite element, transfer matrix and dynamic stiffness matrix methods. However, there are situations that the load will be off centre. This type of loading is called eccentric load. The effect of the eccentricity of axial load on the natural frequencies of asymmetric thin-walled beams is a subject that has not been investigated so far. In this paper, the mentioned effect is studied using exact dynamic stiffness matrix method. Flexure and torsion of the aforesaid thin-walled beam is based on the Bernoulli-Euler and Vlasov theories, respectively. Therefore, the intended thin-walled beam has flexural rigidity, saint-venant torsional rigidity and warping rigidity. In this paper, the Hamilton‟s principle is used for deriving governing partial differential equations of motion and force boundary conditions. Throughout the process, the uniform distribution of mass in the member is accounted for exactly and thus necessitates the solution of a transcendental eigenvalue problem. This is accomplished using the Wittrick-Williams algorithm. Finally, in order to verify the accuracy of the presented theory, the numerical solutions are given and compared with the results that are available in the literature and finite element solutions using ABAQUS software.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.1
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• pp.13-20
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• 2005

This paper addresses a new blind channel equalization method using fourth-order cumulants of channel inputs and a three-layer neural network equalizer. The proposed algorithm is robust with respect to the existence of heavy Gaussian noise in a channel and does not require the minimum-phase characteristic of the channel. The transmitted signals at the receiver are over-sampled to ensure the channel described by a full-column rank matrix. It changes a single-input/single-output (SISO) finite-impulse response (FIR) channel to a single-input/multi-output (SIMO) channel. Based on the properties of the fourth-order cumulants of the over-sampled channel inputs, the iterative algorithm is derived to estimate the deconvolution matrix which makes the overall transfer matrix transparent, i.e., it can be reduced to the identity matrix by simple recordering and scaling. By using this estimated deconvolution matrix, which is the inverse of the over-sampled unknown channel, a three-layer neural network equalizer is implemented at the receiver. In simulation studies, the stochastic version of the proposed algorithm is tested with three-ray multi-path channels for on-line operation, and its performance is compared with a method based on conventional second-order statistics. Relatively good results, withe fast convergence speed, are achieved, even when the transmitted symbols are significantly corrupted with Gaussian noise.