• Communications of the Korean Mathematical Society
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• v.34 no.3
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• pp.799-809
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• 2019

In this note our aim is to extend the Huygens type inequalities to the Bessel and modified Bessel functions of the first kind. Our main motivation to write this note is a recent publication of Zhu, which we wish to complement.

• Communications for Statistical Applications and Methods
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• v.20 no.2
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• pp.157-168
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• 2013

This paper deals with the history of one of the well-known and historically important problems in probability, "Gambler's ruin". This problem was first solved by Pascal and Fermat and published by Huygens in 1657. It was studied and extended by many probabilists in early years and thus, it became an important problem in probability history, introducing many new concepts. We would like to introduce the problem in detail to readers and share the ideas on how new problems are developed, relating to old problems.

• Bulletin of the Korean Space Science Society
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• 2006.04a
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• pp.23-23
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• 2006

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.4
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• pp.326-334
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• 1991

We propose an optical Asynchronous Transfer Mode(ATM) switching system using free-space optics and an output buffer memory. The distributor system in the switching fabric was analyzed using the Huygens-Fresnel principle and lens transformation. For monochromatic illumination, a pattern similar to the Fourier transform of the input distribution was observed across the output plane. A spatially broadened intensity distribution across the the output plane can be expected when the system is illminated with a partially coherent, quasimonochromatic beam. Spatially coherent pulses as short as 100fs can propagate through the distributor without severe spatial broadening.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.6
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• pp.457-461
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• 2013

In this paper, a novel method based on geometrical optics is proposed to calculate the optical characteristics of an electric field driven liquid crystal (ELC) lens. For an optimally designed ELC lens, effective refractive index is calculated and then ray tracing is carried out using Huygens' principle. From the results, the intensity distribution at the optimum viewing distance (OVD) is obtained. To confirm the validity of our work, the result is compared with that calculated by the extended Jones matrix method (EJMM). As a result, it turns out that the novel method provides more simple and rigorous simulation results than the EJMM.

• Smart Structures and Systems
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• v.15 no.4
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• pp.1063-1083
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• 2015

The main purpose of this research is to utilize simple mathematical models to depict the vibration behavior and the resulted sound field of a piezoelectric disk for ultrasonic transducers. Instead of using 1-D vibration model, coupled effect between the thickness and the radial motions was considered to be close to the real vibration behavior. Moreover, Huygens-Fresnel principle was used in both incident and reflected waves to analyze the sound field under obstacles in finite distance. Results of the tested piezoelectric disk show that, discrepancies between the simulation and experiment are 2.5% for resonant frequency and 12% for resulted sound field. Therefore, the proposed method can be used to reduce the complexity in modeling vibration problems, and increase the reliability on analyzing piezoeletric transducers in the design stage.

• Applied Microscopy
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• v.32 no.2
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• pp.81-90
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• 2002

In this review, the author discussed how the Fresnel and Fraunhoffer Diffraction can be deduced from the Huygens-Fresnel principle and Kirchhoff Diffraction Theory. Fresnel diffraction became the basic theory of the CTEM image theory, and Fraunhoffer diffraction became the base for electron diffraction and HRTEM image theory by Fourier transformation. The author also discussed the diffraction based on Born series.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.5
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• pp.421-427
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• 2010

In order to visualize the transfer of sound waves, we performed real-time processing with the fast operating system of GPU, the Graphics Processing Unit. Simulation by using the method of the discrete Huygens' model was also implemented. The sound waves were visualized by varying the real-time processing, the reflecting surfaces within the two-dimensional virtual sound field, and the states of the sound source. Experimental results have shown that reflection and diffraction patterns for the sound waves were identified at the reflecting objects.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.11
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• pp.1023-1026
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• 2016

We calculate the propagation characteristic of antennas considering refractive indices of space environments. The effective indices of troposphere, stratosphere, and inonshpere are computed and the ray tracing method, geometrical optics, and Huygens' principle are used to estimate refracted and attenuated electromagnetic wave of space environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.1
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• pp.29-34
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• 1999

In the paper, the extened Huygens-Fresnel principle has been used to make an analysis of the statistics the received intensity for speckle propagation though the turbulent atmosphere. The results of these formulations include of the log-amplitude covariance as well as the wave structure functions, and It was found that the normalized variance is dependent on the turblence strength and rises above unity.