• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.9
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• pp.493-499
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• 2003

This paper presents exact Autotransformers(ATs)-fed AC electric Railroad system modeling using constant current mode for locomotives. An AC electric railroad system is rapidly changing single-phase load, and at a feeding substation, 3-phase electric power is transferred to paired directional single-phase electric power. As the train moves along a section of line between two adjacent ATs. The proposed AC electric railroad system modeling method considers the line self-impedances and mutual-impedances. The constant current mode model objectives are to calculate the catenary and rail voltages with the loop equation. When there are more than one train in the AC electric railroad system, the principle of superposition applies and the only difference between the system analyses for one train. Filially, this paper shows the general equation of an AC electric railroad system, and that equation has no relation with trains number, trains position, and feeding distance.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.1
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• pp.31-37
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• 2001

A robust adaptive technique for the longitudinal control of a platoon of automated vehicles is presented. A nonlinear model is used to represent the dynamics of each vehicle within the platoon. The external disturbances such as wind gust and a disturbance term due to engine transmission variations and so on are considered. The state observer is used to avoid direct measurement of the relative velocity or acceleration between the controlled and leading vehicles or the controlled vehicles's acceleration. The proposed controller guarantees to recover platoon stability in operation even if a speed dependent spacing policy is adopted, which incorporates a constant time headway in addition to the constant distance. It is shown that the proposed observer is exponentially stable, and the at the robust adaptive controller is stable. The simulation results demonstrate excellent tracking even in the presence of disturbances.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.771-775
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• 2011

This paper presents design process of linear induction motor in dynamic tester for catenary-current collection. To minimize length of rail for dynamic tester for catenary-current collection, accelerating performance of the linear induction motor is very important. So the design process of linear induction motor considered in this paper is different with general design process of linear induction motor, because dynamic tester has three type driving region, as accelerating region, constant speed region, and braking region. Considering accelerating performance of motor, distance and time from starting point to constant speed region were concerned for load condition of motor. Designed linear induction motor was analyzed by 2-dimensional finite element method. Using mechanical dynamics simulation with analysis result of 2-dimensional finite element method and accelerating performance of designed motor was proved.

• Journal of Photoscience
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• v.12 no.1
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• pp.11-15
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• 2005

The mechanism of interaction of two drugs viz., amoxicillin and cloxacillin with bovine serum albumin has been investigated using fluorescence absorption and circular dichroism spectroscopy. The quenching mechanism of fluorescence of bovine serum albumin by amoxicillin and cloxacillin was discussed. The binding sites number n and apparent binding constant Kwere measured by fluorescence quenching method. The thermodynamic parameters obtained from data at different temperatures were calculated. The distance r between donor (bovine serum albumin) and acceptor (amoxicillin and cloxacillin) was obtained according to Forster theory of non-radiative energy transfer. The effect of common ions on binding constant was also investigated. The results of synchronous fluorescence spectra, UV-vis absorption spectra and circular dichroism of BSA in presence of amoxicillin and cloxacillin show that the conformation of bovine serum albumin changed

• Interaction and multiscale mechanics
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• v.3 no.2
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• pp.157-171
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• 2010

In this paper, a theoretical method has been developed for the electric double layer interaction under condition of the variable dielectric permittivity of water. Using Poisson-Boltzmann equation (PBE), for one plate and two plates having similar or dissimilar constant charge or constant potential, we have investigated the electric double layer potential, its gradient and the disjoining pressure as well as the effect of variation of dielectric permittivity on these parameters. It has been assumed that plates are separated by a specific distance and contain a liquid solution in between. It is shown that reduction of the dielectric permittivity near the interfaces results in compression of electric double layers and affects the potential and its gradient which leads to a decreased electrostatic repulsion. In addition, it is shown that variation of dielectric permittivity in the case of higher electrolyte concentration, leads to a greater change in potential distribution between two plates.

• Current Optics and Photonics
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• v.1 no.1
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• pp.45-50
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• 2017

Optical instruments based on polymer-dispersed liquid crystal (PDLC) have been used to inspect transparent electrodes. Generally the operating voltage of an inspection instrument using PDLC is very high, over 300 V, reducing its lifetime and reliability. The operating-voltage issue becomes more serious in the inspection of touch-screen panel (TSP) electrodes, due to the bezel structure protruding over the electrodes. We have theoretically calculated the parameters affecting the operating voltage as a function of the distance between the TSP and the PDLC, the thickness, and the dielectric constant of the sublayers when the inspection module was away from the TSP electrodes. We have experimentally verified the results, and have proposed a way to reduce the operating voltage by substituting a plastic substrate film with a hard coating layer of smaller thickness and higher dielectric constant.

• Journal of the Korean Institute of Telematics and Electronics
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• v.23 no.5
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• pp.591-596
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• 1986

A binary continuous phase frequency shift keying (CPFSK), whose phase is a continuous function of time and instantaneous frequency is constant, is a bandwidth efficient constant envelope signalling scheme. A transmitting signal is formed by combined coding of a convolutional encoder and a binary CPFSK modulator. The signal is transmitted throuth additive white Gaussian noise(AWGN) channel. If the received signal is detected by a coherent maximum likelihood(ML) receiver, error probability can be expressed approximately in terms of minimum Euclidean distance. We propose rate 2/4 codes for the improvement of error performance without increating the data rate per bandwidth and the receiver complexity. Its minimum Euclidean distances are compared with those of rate \ulcornercodes as a function of modulation index and observation interval.

• Kyungpook Mathematical Journal
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• v.63 no.2
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• pp.199-223
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• 2023

We introduce the constants E[t, X], C_NJ[X] and J[t, X] to describe the asymmetry of the norm. They can be seen as the skew version of the Gao's parameter, von Neumann-Jordan constant and Milman's moduli, respectively. We establish basic properties of these constants, relating them other well known constants, and use these properties to calculate the constants for specific spaces. We then use these constants to study Hilbert spaces, uniformly non-square spaces and their normal structures. With the Banach-Mazur distance, we use them to study isomorphic Banach spaces.

• Journal of Mechanical Science and Technology
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• v.17 no.3
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• pp.321-328
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• 2003

The elongation of contact length on the line of action is considered with particular reference for roll forming of gears, and for dynamic behavior of the tooth in meshing. However there is no paper that discuss the elongation of contact length in the load meshing of gears. Based on our investigation, the contact length on the line of action elongates more than the kinematically calculated value. In rolling, as the tool approaches the workpiece, the center distance of the gears decreases by a small amount. But, the elongation of contact length is sensitive. Therefore, the contact point on the line of action is difficult to be determined, which complicates the tooth analysis. In this study, the exact relation between the elongation of contact length and the tooth space over the recess or before the approach are revealed by experiments and kinematic theory. This analytical result applies not only for rolling, but also for the single flank meshing which is done under constant center distance.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.12
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• pp.3352-3359
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• 1995

An Eulerian-Lagrangian method is employed to simulate the ignition process and the flame propagation through the air/fuel spray mixture in a closed constant-volume combustor. The spray mixture is ignited by providing a hot wall at the end of the combustor or by firing the electric spark. The investigated parameters involve the initial droplet size, overall equivalence ratio, initial fuel vapor concentration, distance between the hot wall and the nearest droplet, and the ignition energy. Numerical results clearly show the existence of the optimum spray condition for minimizing the ignition energy and the ignition delay time as well as the critical dependence of ignition upon the distance of the heat source to the nearest droplet.